chore: update release_level in repo-metadata.json (googleapis#1642)

* chore: update .repo-metadata.json

* revert

* remove api_shortname

Author: parthea

Diff for: .repo-metadata.json

@@ -3,7 +3,7 @@
     "name_pretty": "Google API Python Client",
     "client_documentation": "https://github.com/googleapis/google-api-python-client/tree/main/docs#google-api-client-library-for-python-docs",
     "issue_tracker": "https://github.com/googleapis/google-api-python-client/issues",
-    "release_level": "ga",
+    "release_level": "stable",
     "language": "python",
     "library_type": "REST",
     "repo": "googleapis/google-api-python-client",