3.4.0 & 3.4.1-RC1 Release procedure

[Kordyjan]

Switch development from 3.4.1 to 3.4.2

• [x] Create branch release-3.4.1 from main
• [x] On main in Build.scala: Set baseVersion to 3.4.2:
  • https://github.com/lampepfl/dotty/pull/19683

Publish 3.4.0 artifacts to Maven Central via CI:

• [x] On release-3.4.0 branch:
  • [x] In Build.scala: Set baseVersion to 3.4.0
  • [x] In Build.scala: Set previousDottyVersion to 3.3.1
  • [x] Set the TASTy version to 28.4-0
  • [x] In changelogs add file with a changelog
• [x] Tag the branch as 3.4.0
• Build

Set bootstrapping for future versions on main:

• [x] In Build.scala: Set previousDottyVersion to 3.4.0
• [x] In Build.scala: Set referenceVersion to 3.4.0
• [x] Check and update project/MiMaFilters.scala

Publish 3.4.1-RC1 artifacts to Maven Central via CI:

• [x] On release-3.4.1 branch
  • [x] In Build.scala: Set previousDottyVersion to 3.4.0
  • [x] In Build.scala: Set referenceVersion to 3.4.0
  • [x] In Build.scala: Set baseVersion to 3.4.1-RC1
  • [x] Check and update project/MiMaFilters.scala
  • [x] In changelogs add file with a changelog
• [x] Tag the branch as 3.4.1-RC1
• Build

Set bootstrapping for future versions version on main:

• [ ] In Build.scala: Set previousDottyVersion to 3.4.1-RC1
• [ ] In Build.scala: Set referenceVersion to 3.4.0
• [ ] Check and update project/MiMaFilters.scala

Confirm that the tooling is working correctly:

• Metals (@tgodzik):
  • [x] 3.4.0
  • [x] 3.4.1-RC1
• Scala CLI:
  • [x] 3.4.0
  • [x] 3.4.1-RC1
• Scala Native (@WojciechMazur):
  • [x] 3.4.0
  • [x] 3.4.1-RC1
• Scastie:
  • [x] 3.4.0
  • [x] 3.4.1-RC1
• Scala DAP (@adpi2):
  • [x] 3.4.0
  • [x] 3.4.1-RC1

Update the ecosystem:

• [ ] Release 3.4.0 to SDKMAN
• [ ] Update the templates and examples projects:
  • [ ] scala3-mill-example-project
  • [ ] scala3-cross.g8
  • [ ] scala3-staging.g8
  • [ ] scala3-tasty-inspector.g8
  • [ ] scala3.g8

Prepare the documentation:

• [ ] Merge release-3.4.0 into language-reference-stable
• [ ] Publish API docs for 3.4.0
• [ ] Add 3.4.0 to the version list in API docs
• [ ] Update docs.scala-lang

Announce the releases:

• [ ] Make both GitHub releases public
• [ ] Publish a post on https://scala-lang.org/blog
• [ ] Open the 3.4.1 tracking thread on https://contributors.scala-lang.org
• [x] Close the 3.4.0 milestone
• [x] Make sure all PRs merged and issues fixed in 3.4.1 are in the 3.4.1 milestone