3.2.1-RC2 Release procedure

[Kordyjan]

• Backport relevant changes:
  • Backport "Only look for synthetic applies under TypeApply with inferred arguments" #16044
  • Backport "Improvements for implicit searches with top-level type variables" #16045
  • Backport "Better types for class type parameters" #16046
  • Backport "Avoid adding NoSymbol to gadt constraints in TypeOps.instantiateToSubType" #16047
• Publish artifacts to Maven via CI
  • On release-3.2.1 branch:
    • In Build.scala: Set baseVersion to 3.2.1-RC2
    • In Build.scala: Set previousDottyVersion to 3.2.1-RC1
    • in changelogs add file with a changelog
    • Tag the branch as 3.2.1-RC2
• On main (Set reference version to 3.2.1-RC2 #16054):
  • In Build.scala: Set referenceVersion to 3.2.1-RC2
• Announce the release
  • Publish release on GitHub Releases
  • Comment on the announcement thread on https://contributors.scala-lang.org/t/3-2-1-release-thread/5912