Avoid hardcoded TFMs in source-code

[ViktorHofer]

https://github.com/search?q=repo%3Adotnet%2Fefcore%20net8.0&type=code

efcore/src/EFCore.Tasks/buildTransitive/Microsoft.EntityFrameworkCore.Tasks.props

Line 5 in e771c0f

<_TaskTargetFramework Condition="'$(MSBuildRuntimeType)' == 'Core'">net10.0</_TaskTargetFramework>

These hardcodes make it harder to update the TFM centrally (i.e. when updating the TargetFrameworkDefault properties in Arcade).

• All the hardcoded TFMs in shipping .props / .targets files can be avoided by changing the "tools//" package paths to "tools/net/" and "tools/netframework/". The TFM version doesn't provide value there. We already do this in arcade, sourcelink and will likely soon in sdk as well.

This is in reaction to dotnet/dotnet@985a8fe which we had to do in the VMR when updated the TFM properties.