Update deprecated package System.Diagnostics.DiagnosticSource

[cremor]

• List of NuGet packages and version that you are using: Microsoft.ApplicationInsights 2.22.0
• Runtime version (e.g. net461, net48, netcoreapp2.1, netcoreapp3.1, etc. You can find this information from the *.csproj file): All currently supported
• Hosting environment (e.g. Azure Web App, App Service on Linux, Windows, Ubuntu, etc.): Not relevant

Describe the bug

The Microsoft.ApplicationInsights NuGet package depends on the System.Diagnostics.DiagnosticSource package in version 5.0.0. That version is deprecated and should be updated.

Note that the current package version 8.0.1 doesn't support the target frameworks net452 and net46 and more. So the target framework of Microsoft.ApplicationInsights has to be updated to net462 (netstandard2.0 can stay).

To Reproduce

Check the deprecation status of the NuGet package System.Diagnostics.DiagnosticSource in version 5.0.0

[MichaelSimons]

This is something the .NET project recently encountered as it has a dependency on Application Insights. Applications Insights is included in the .NET build dependency graph when "source building" for inclusion in Linux distros. We could easily patch this dependency as we exclude all Net FX tfms in our build. I wanted to upstream this upgrade but quickly discovered this was going to require a lot of changes to upgrade the net452 and net46 tfms.