Backport sonatype / gpg changes from 2.13.x to 2.12.x

[lrytz]

• update publishing scripts for central repository scala#11141
• Fixes for central repository publishing scala#11142
• Switch GPG key for signing releases, use the same as Scala 3 scala#11158

[SethTisue]

done?

[lrytz]

👍 I think so. Maybe there's some changes to backport in scala-dist, I'll check.