NuGet.Build.Tasks.Console should roll forward to newer runtimes

[dfederm]

NuGet Product Used

Other/NA

Product Version

6.5.0

Worked before?

N/A

Impact

It's more difficult to complete my work

Repro Steps & Context

The NuGet.Build.Tasks.Console package contains a runnable app that is built against .NET 5. When this component is inserted into the .NET SDK, the insertion process generates a runtimeconfig that re-targets the application against whatever version of the runtime is being built.

This means that the NuGet.Build.Tasks.Console application can't be used in a custom way without regenerating the runtimeconfig. If the existing runtimeconfig had rollFoward: latestMajor then it would work in all runtimes greater than or equal to .NET 5.

{
  "runtimeOptions": {
    "tfm": "net5.0",
    "rollFoward": "latestMajor",
    "framework": {
      "name": "Microsoft.NETCore.App",
      "version": "5.0.0"
    },
    "configProperties": {
      "System.GC.Server": true,
      "System.Reflection.Metadata.MetadataUpdater.IsSupported": false
    }
  }
}

Verbose Logs

No response

[dfederm]

As per #5125, adding RollForward should also address this issue in a different way.