chore(nodejs): update client ref docs link in metadata (#483)

Author: fhinkel

packages/google-cloud-bigquery-datatransfer/.repo-metadata.json

@@ -2,7 +2,7 @@
   "default_version": "v1",
   "release_level": "ga",
   "requires_billing": true,
-  "client_documentation": "https://googleapis.dev/nodejs/bigquery-data-transfer/latest",
+  "client_documentation": "https://cloud.google.com/nodejs/docs/reference/bigquery-data-transfer/latest",
   "codeowner_team": "@googleapis/api-bigquery",
   "language": "nodejs",
   "issue_tracker": "https://issuetracker.google.com/savedsearches/559654",

packages/google-cloud-bigquery-datatransfer/README.md

@@ -167,7 +167,7 @@ Apache Version 2.0
 
 See [LICENSE](https://github.com/googleapis/nodejs-bigquery-data-transfer/blob/master/LICENSE)
 
-[client-docs]: https://googleapis.dev/nodejs/bigquery-data-transfer/latest
+[client-docs]: https://cloud.google.com/nodejs/docs/reference/bigquery-data-transfer/latest
 [product-docs]: https://cloud.google.com/bigquery/transfer/
 [shell_img]: https://gstatic.com/cloudssh/images/open-btn.png
 [projects]: https://console.cloud.google.com/project