Release Scala 2.13.11-M1

[SethTisue]

context is https://github.com/scala/scala/pull/10306 — we need to re-bootstrap in order to test on JDK 20

Prepare

• [x] Merge 2.12.x forward onto 2.13.x

Stage

• [x] Make sure there are no stray staging repos on Sonatype
• [x] Trigger a custom build on travis
  • Select the correct branch
  • Custom config: before_script: export SCALA_VER_BASE=2.13.11 SCALA_VER_SUFFIX=-M1
  • https://app.travis-ci.com/github/scala/scala/jobs/597378990
• [x] Wait for the build to finish, check contents of staging repos
• [x] Create the scala/scala tag locally: git tag -s -m "Scala 2.13.11-M1" v2.13.11-M1 44c600610ad076468708de0702fb2a76c5a7e15c

Release! (point of hard no-return)

• [x] Push scala/scala tag: git push https://github.com/scala/scala.git v2.13.11-M1
• [x] Promote staging repos (using oss.sonatype.org web UI)

Check availability

• [x] Find the release on maven central: https://repo1.maven.org/maven2/org/scala-lang/scala-compiler/2.13.11-M1/

Afterwards

• [x] Create a scala/scala PR to:
  • [x] update starr.version in /versions.properties