openapi-diff requires very old and unsupported version of DotNet framework

[mkistler]

Attempt to run openapi-diff on MacOS (Catalina) fails with the follow output:

>oad compare <file1> <file2>            
Error: Command failed: dotnet /usr/local/lib/node_modules/@azure/oad/dlls/OpenApiDiff.dll -o /var/folders/wp/2g14y2fx1rb4mxc_3rs_vvlm0000gn/T/old-resolved.json -n /var/folders/wp/2g14y2fx1rb4mxc_3rs_vvlm0000gn/T/new-resolved.json
It was not possible to find any compatible framework version
The framework 'Microsoft.NETCore.App', version '2.0.0' was not found.
  - The following frameworks were found:
      5.0.7 at [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

You can resolve the problem by installing the specified framework and/or SDK.

The specified framework can be found at:
  - https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=2.0.0&arch=x64&rid=osx.10.15-x64

    at ChildProcess.exithandler (node:child_process:326:12)
    at ChildProcess.emit (node:events:394:28)
    at maybeClose (node:internal/child_process:1067:16)
    at Process.ChildProcess._handle.onexit (node:internal/child_process:301:5) {

Note that I have the current version of DotNet, 5.0.7, installed. But openapi-diff refuses to use that, directing me to instead install the 2.0.0 version. But the supplied URL takes me to a page with this warning:

Do I really have to use an old, unsupported, possibly vulnerable to security issues version of the DotNet runtime to use this tool?

[jianyexi]

already upgraded to LTS dotnet core 3.1