Add RollForward to NuGet.Build.Tasks.Console

[dfederm]

Bug

Fixes: #12528

Regression? Last working version: N/A

Description

Currently, NuGet.Build.Tasks.Console contains an executable which targets the .NET 5 runtime, so to use the package either the .NET 5 runtime (an EOL runtime) needs to be installed, or as the insertion process does the application is retargetted on the fly.

This change adds rollforward to the runtimeconfig so that the application is runnable on newer versions of the runtime. In theory, this makes the retargetting unnecessary, but I'm not proposing that process changes for now.

Note: for context, NuGet.Build.Tasks.Console is either told where to find dotnet explicitly, or it just looks two directories up for it. So this change just allows either of those to be newer runtimes and not just crash.

Additionally, the NuGet.Build.Tasks.Console package is used in the MSBuild boottrapper, which is a fundamental part of MSBuild's CI process (it builds, then uses the output to build itself again with the new bits). So this would bring that scenario a bit more inline with how it actually works in the SDK.

FYI @jeffkl with whom I discussed offline

PR Checklist

• PR has a meaningful title

• PR has a linked issue.

• Described changes

• Tests

  • Automated tests added
  • OR
  • Test exception
  • OR
  • N/A

• Documentation

  • Documentation PR or issue filled
  • OR
  • N/A