Update sbt to 1.4.9 (#368)

scala-steward · web-flow · commit de1ae3d7a7f7 · 2021-03-15T10:15:06.000+01:00
[skip ci]
diff --git a/project/build.properties b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.4.7
+sbt.version=1.4.9
