chore(metadata): this client is already beta (#34)

.repo-metadata.json

@@ -4,10 +4,10 @@
   "product_documentation": "https://cloud.google.com/bigquery/docs/reference/storage/",
   "client_documentation": "https://googleapis.dev/java/google-cloud-bigquerystorage/latest",
   "issue_tracker": "https://issuetracker.google.com/savedsearches/559654",
-  "release_level": "alpha",
+  "release_level": "beta",
   "language": "java",
   "repo": "googleapis/java-bigquerystorage",
   "repo_short": "java-bigquerystorage",
   "distribution_name": "com.google.cloud:google-cloud-bigquerystorage",
   "api_id": "bigquerystorage.googleapis.com"
-}
+}