docs(fix): update client documentation link (#192)

.repo-metadata.json

@@ -3,7 +3,7 @@
   "name_pretty": "Cloud Pub/Sub",
   "api_reference": "https://cloud.google.com/pubsub/",
   "product_documentation": "https://cloud.google.com/pubsub/docs/",
-  "client_documentation": "https://googleapis.dev/java/google-cloud-pubusb/latest/index.html",
+  "client_documentation": "https://googleapis.dev/java/google-cloud-pubsub/latest/index.html",
   "api_description": "is designed to provide reliable, many-to-many, asynchronous messaging between applications. Publisher applications can send messages to a topic and other applications can subscribe to that topic to receive the messages. By decoupling senders and receivers, Google Cloud Pub/Sub allows developers to communicate between independently written applications.",
   "issue_tracker": "https://issuetracker.google.com/savedsearches/559741",
   "release_level": "ga",