Release 3.1.0-RC2

[Kordyjan]

• Have [Backport] Fix #10747: Raise type error on unreducible match type #13519 merged
• Have [Backport] Set typer phase after InteractiveDriver.run #13534 merged
• Publish artifacts to Maven via CI
  • On release-3.1.0 branch
    • In Build.scala: Set baseVersion to 3.1.0-RC2
    • In Build.scala: Set previousDottyVersion according to the instructions in the comment to that variable.
    • In tasty/src/dotty/tools/tasty/TastyFormat.scala: Set the correct tasty version according to Verify TASTy versions before releases #13447
    • In Build.scala: Set referenceVersion to 3.1.0-RC1
    • Tag the branch as 3.1.0-RC2
• Announce the release
  • Publish releases for the RC and stable versions on GitHub Releases
  • Make an announcement thread on https://contributors.scala-lang.org