Update sbt, scripted-plugin to 1.12.8 (#1636)

Co-authored-by: zio-scala-steward[bot] <145262613+zio-scala-steward[bot]@users.noreply.github.com>

Author: zio-scala-steward[bot]

project/build.properties

@@ -1 +1 @@
-sbt.version = 1.12.7
+sbt.version = 1.12.8