chore(nodejs): update client ref docs link in metadata (#567)

Author: fhinkel

packages/google-cloud-monitoring/.repo-metadata.json

@@ -1,5 +1,5 @@
 {
-  "client_documentation": "https://googleapis.dev/nodejs/monitoring/latest",
+  "client_documentation": "https://cloud.google.com/nodejs/docs/reference/monitoring/latest",
   "product_documentation": "https://cloud.google.com/monitoring/docs",
   "name": "monitoring",
   "requires_billing": true,

packages/google-cloud-monitoring/README.md

@@ -194,7 +194,7 @@ Apache Version 2.0
 
 See [LICENSE](https://github.com/googleapis/nodejs-monitoring/blob/master/LICENSE)
 
-[client-docs]: https://googleapis.dev/nodejs/monitoring/latest
+[client-docs]: https://cloud.google.com/nodejs/docs/reference/monitoring/latest
 [product-docs]: https://cloud.google.com/monitoring/docs
 [shell_img]: https://gstatic.com/cloudssh/images/open-btn.png
 [projects]: https://console.cloud.google.com/project