Cannot publish a project that uses Tavis.UriTemplates due to package downgrade errors

[KristofVerbiest]

I have a project that depends on Tavis.UriTemplates and that I want to publish for the linux-arm runtime. This fails due to 'package downgrade' errors. The full error is included below.

All these steps are necessary to reproduce the error:

• Create a new Console assembly (.net core)
• Add a nuget reference to Tavis.UriTemplate
• Add a nuget reference to Microsoft.AspNetCore.SignalR.Protocols.MessagePack (the problem will also occur with other packages)
• Build the project --> no error yet
• Publish the assembly using dotnet publish -c Release -r linux-arm --> error

This is my project file:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.SignalR.Protocols.MessagePack" Version="3.1.2" />
    <PackageReference Include="Tavis.UriTemplates" Version="1.1.1" />
  </ItemGroup>

</Project>

The full error I get is:

C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.InteropServices from 4.3.0 to 4.1.0. Reference the package directly from the project to se
lect a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> Microsoft.Win32.Primitives 4.0.1 -> runtime.unix.Microsoft.W
in32.Primitives 4.3.0 -> System.Runtime.InteropServices (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.InteropServices (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.IO.FileSystem.Primitives from 4.3.0 to 4.0.1. Reference the package directly from the project to s
elect a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Console 4.0.0 -> runtime.unix.System.Console 4.3.0 ->
 System.IO.FileSystem.Primitives (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem.Primitives (>= 4.0.1)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.Extensions from 4.3.0 to 4.1.0. Reference the package directly from the project to select
a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Console 4.0.0 -> runtime.unix.System.Console 4.3.0 ->
 System.Runtime.Extensions (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.Extensions (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.Handles from 4.3.0 to 4.0.1. Reference the package directly from the project to select a d
ifferent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Console 4.0.0 -> runtime.unix.System.Console 4.3.0 ->
 System.Runtime.Handles (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.Handles (>= 4.0.1)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.InteropServices from 4.3.0 to 4.1.0. Reference the package directly from the project to se
lect a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Console 4.0.0 -> runtime.unix.System.Console 4.3.0 ->
 System.Runtime.InteropServices (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.InteropServices (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Text.Encoding.Extensions from 4.3.0 to 4.0.11. Reference the package directly from the project to
select a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Console 4.0.0 -> runtime.unix.System.Console 4.3.0 ->
 System.Text.Encoding.Extensions (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Text.Encoding.Extensions (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Threading from 4.3.0 to 4.0.11. Reference the package directly from the project to select a differ
ent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Console 4.0.0 -> runtime.unix.System.Console 4.3.0 ->
 System.Threading (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Threading (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Diagnostics.Debug from 4.3.0 to 4.0.11. Reference the package directly from the project to select
a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem 4.0.1 -> runtime.unix.System.IO.FileSys
tem 4.3.0 -> System.Diagnostics.Debug (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Diagnostics.Debug (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.IO.FileSystem.Primitives from 4.3.0 to 4.0.1. Reference the package directly from the project to s
elect a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem 4.0.1 -> runtime.unix.System.IO.FileSys
tem 4.3.0 -> System.IO.FileSystem.Primitives (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem.Primitives (>= 4.0.1)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.Extensions from 4.3.0 to 4.1.0. Reference the package directly from the project to select
a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem 4.0.1 -> runtime.unix.System.IO.FileSys
tem 4.3.0 -> System.Runtime.Extensions (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.Extensions (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.Handles from 4.3.0 to 4.0.1. Reference the package directly from the project to select a d
ifferent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem 4.0.1 -> runtime.unix.System.IO.FileSys
tem 4.3.0 -> System.Runtime.Handles (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.Handles (>= 4.0.1)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.InteropServices from 4.3.0 to 4.1.0. Reference the package directly from the project to se
lect a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem 4.0.1 -> runtime.unix.System.IO.FileSys
tem 4.3.0 -> System.Runtime.InteropServices (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.InteropServices (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Text.Encoding.Extensions from 4.3.0 to 4.0.11. Reference the package directly from the project to
select a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem 4.0.1 -> runtime.unix.System.IO.FileSys
tem 4.3.0 -> System.Text.Encoding.Extensions (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Text.Encoding.Extensions (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Threading from 4.3.0 to 4.0.11. Reference the package directly from the project to select a differ
ent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem 4.0.1 -> runtime.unix.System.IO.FileSys
tem 4.3.0 -> System.Threading (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Threading (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: Microsoft.Win32.Primitives from 4.3.0 to 4.0.1. Reference the package directly from the project to select
 a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Primitives 4.0.11 -> runtime.unix.System.Net.Prim
itives 4.3.0 -> Microsoft.Win32.Primitives (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> Microsoft.Win32.Primitives (>= 4.0.1)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Diagnostics.Tracing from 4.3.0 to 4.1.0. Reference the package directly from the project to select
 a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Primitives 4.0.11 -> runtime.unix.System.Net.Prim
itives 4.3.0 -> System.Diagnostics.Tracing (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Diagnostics.Tracing (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.Extensions from 4.3.0 to 4.1.0. Reference the package directly from the project to select
a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Primitives 4.0.11 -> runtime.unix.System.Net.Prim
itives 4.3.0 -> System.Runtime.Extensions (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.Extensions (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.Handles from 4.3.0 to 4.0.1. Reference the package directly from the project to select a d
ifferent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Primitives 4.0.11 -> runtime.unix.System.Net.Prim
itives 4.3.0 -> System.Runtime.Handles (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.Handles (>= 4.0.1)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.InteropServices from 4.3.0 to 4.1.0. Reference the package directly from the project to se
lect a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Primitives 4.0.11 -> runtime.unix.System.Net.Prim
itives 4.3.0 -> System.Runtime.InteropServices (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.InteropServices (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Threading from 4.3.0 to 4.0.11. Reference the package directly from the project to select a differ
ent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Primitives 4.0.11 -> runtime.unix.System.Net.Prim
itives 4.3.0 -> System.Threading (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Threading (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Diagnostics.Debug from 4.3.0 to 4.0.11. Reference the package directly from the project to select
a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.Diagnostics.Debug (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Diagnostics.Debug (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Diagnostics.Tracing from 4.3.0 to 4.1.0. Reference the package directly from the project to select
 a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.Diagnostics.Tracing (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Diagnostics.Tracing (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.IO.FileSystem from 4.3.0 to 4.0.1. Reference the package directly from the project to select a dif
ferent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.IO.FileSystem (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem (>= 4.0.1)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Net.Primitives from 4.3.0 to 4.0.11. Reference the package directly from the project to select a d
ifferent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.Net.Primitives (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Primitives (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.Extensions from 4.3.0 to 4.1.0. Reference the package directly from the project to select
a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.Runtime.Extensions (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.Extensions (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.Handles from 4.3.0 to 4.0.1. Reference the package directly from the project to select a d
ifferent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.Runtime.Handles (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.Handles (>= 4.0.1)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Runtime.InteropServices from 4.3.0 to 4.1.0. Reference the package directly from the project to se
lect a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.Runtime.InteropServices (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Runtime.InteropServices (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Threading from 4.3.0 to 4.0.11. Reference the package directly from the project to select a differ
ent version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.Threading (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Threading (>= 4.0.11)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: System.Diagnostics.Tracing from 4.3.0 to 4.1.0. Reference the package directly from the project to select
 a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.IO.FileSystem 4.0.1 -> runtime.unix.System.IO.FileSys
tem 4.3.0 -> System.Buffers 4.3.0 -> System.Diagnostics.Tracing (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Diagnostics.Tracing (>= 4.1.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605: Detected package downgrade: Microsoft.Win32.Primitives from 4.3.0 to 4.0.1. Reference the package directly from the project to select
 a different version.
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> System.Net.Sockets 4.1.0 -> runtime.unix.System.Net.Sockets
4.3.0 -> System.Net.NameResolution 4.3.0 -> System.Security.Principal.Windows 4.3.0 -> Microsoft.Win32.Primitives (>= 4.3.0)
C:\Git\Tavis.UriTemplates\ConsoleApp1\ConsoleApp1.csproj : error NU1605:  ConsoleApp1 -> Tavis.UriTemplates 1.1.1 -> NETStandard.Library 1.6.0 -> Microsoft.Win32.Primitives (>= 4.0.1)

[KristofVerbiest]

In the meantime this is a workaround: https://github.com/dotnet/core/issues/907 The new project (that does not have the problem) is

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
    <WarningsAsErrors />
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
    <WarningsAsErrors />
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.SignalR.Protocols.MessagePack" Version="3.1.2" />
    <PackageReference Include="Tavis.UriTemplates" Version="1.1.1" />
  </ItemGroup>

</Project>

Note the empty 'WarningAsErrors' nodes.