chore(pubsub/v2): add repo-metadata for v2 veneer (googleapis#13886)

Add metadata for Pub/Sub API v2

Author: hongalex

pubsub/v2/.repo-metadata.json

@@ -0,0 +1,10 @@
+{
+  "api_shortname": "pubsub",
+  "client_documentation": "https://cloud.google.com/go/docs/reference/cloud.google.com/go/pubsub/v2/latest",
+  "client_library_type": "manual",
+  "description": "Pub/Sub API",
+  "distribution_name": "cloud.google.com/go/pubsub/v2",
+  "language": "go",
+  "library_type": "GAPIC_MANUAL",
+  "release_level": "stable"
+}