Update sbt, scripted-plugin to 1.12.9#1304

scala-steward wants to merge 1 commit intopbernet:migrate_pekkopbernet/akka_streams_tutorial:migrate_pekkofrom

scala-steward:update/sbt-1.12.9scala-steward/akka_streams_tutorial:update/sbt-1.12.9Copy head branch name to clipboard