chore(deps): update dependency google-cloud-monitoring to v2.13.0 (#716)

Author: renovate-bot

packages/google-cloud-bigtable/samples/metricscaler/requirements.txt

@@ -1,2 +1,2 @@
 google-cloud-bigtable==2.14.1
-google-cloud-monitoring==2.12.0
+google-cloud-monitoring==2.13.0