Update sbt to 1.5.6 (#424)

scala-steward · web-flow · commit 7593b214a0a5 · 2021-12-13T23:22:22.000Z
diff --git a/project/build.properties b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.5.4
+sbt.version=1.5.6
