changelog: adds note for #13607

CHANGELOG.md

@@ -16,6 +16,7 @@
 # 5.3.1 (unreleased)
 
 * **Render**: Fix PhantomJS render of graph panel when legend displayed as table to the right [#13616](https://github.com/grafana/grafana/issues/13616)
+* **Stackdriver**: Filter option disappears after removing initial filter [#13607](https://github.com/grafana/grafana/issues/13607)
 
 # 5.3.0 (2018-10-10)