3.2.0-RC2 Release procedure

[Kordyjan]

• Publish artifacts to Maven via CI
  • On release-3.2.0 branch:
    • In Build.scala: Set baseVersion to 3.2.0-RC2
    • In Build.scala: Set previousDottyVersion to 3.2.0-RC1
    • in changelogs add file with a changelog
    • Tag the branch as 3.2.0-RC2
• On master:
  • In Build.scala: Set referenceVersion to 3.2.0-RC2
• Announce the release
  • Publish release on GitHub Releases
  • Comment on the announcement thread on https://contributors.scala-lang.org

[bishabosha]

we need to backport #15593