Add post-update hook for OrganizeImports

Author: fthomas

modules/core/src/main/resources/default.scala-steward.conf

@@ -1,4 +1,11 @@
 postUpdateHooks = [
+  {
+    groupId = "com.github.liancheng",
+    artifactId = "organize-imports",
+    command = ["sbt", "scalafixAll"],
+    commitMessage = "Reorganize imports with OrganizeImports ${nextVersion}",
+    addToGitBlameIgnoreRevs = true
+  },
   {
     groupId = "com.lightbend.sbt",
     artifactId = "sbt-java-formatter",