Update sbt, scripted-plugin to 1.12.9 (#696)

Co-authored-by: typelevel-steward[bot] <106827141+typelevel-steward[bot]@users.noreply.github.com>

Author: typelevel-steward[bot]

project/build.properties

@@ -1 +1 @@
-sbt.version=1.12.8
+sbt.version=1.12.9