message: chore!: set release level to GA
diff: "product_documentation": "https://cloud.google.com/pubsub/docs/",
  "client_documentation": "https://googleapis.dev/nodejs/pubsub/latest",
  "issue_tracker": "https://issuetracker.google.com/savedsearches/559741",
  - "release_level": "beta",
  + "release_level": "ga",
  "language": "nodejs",
  "repo": "googleapis/nodejs-pubsub",
  "distribution_name": "@google-cloud/pubsub",
  