Update to 2.12.8

Changelog: https://github.com/scala/scala/releases/tag/v2.12.8

scala changes the license from BSD to Apache: https://www.scala-lang.org/news/license-change.html

PR: 233973
Submitted by: j-keck <jhyphenkeck@gmail.com> (maintainer)
Sponsored by: Netzkommune GmbH