Amazon Relational Database Service Update: Adds waiters support for DBCluster.

Author: AWS

.changes/next-release/feature-AmazonRelationalDatabaseService-9a350fa.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "Amazon Relational Database Service",
+    "contributor": "",
+    "description": "Adds waiters support for DBCluster."
+}