Enable GitHub actions dependency updates

Author: marko-bekhta

.github/dependabot.yml

@@ -10,3 +10,10 @@ updates:
           - "*maven*plugin*"
           - "*plexus*"
           - "org.apache.maven*:*"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: monthly
+    allow:
+      - dependency-name: "actions/*"
+      - dependency-name: "redhat-actions/*"