README: mark pubsub stable
@@ -268,7 +268,7 @@ Google API | Status | Package
[Logging][cloud-logging] | stable | [`cloud.google.com/go/logging`][cloud-logging-ref]
[Monitoring][cloud-monitoring] | beta | [`cloud.google.com/go/monitoring/apiv3`][cloud-monitoring-ref]
[OS Login][cloud-oslogin] | alpha | [`cloud.google.com/compute/docs/oslogin/rest`][cloud-oslogin-ref]
-[Pub/Sub][cloud-pubsub] | beta | [`cloud.google.com/go/pubsub`][cloud-pubsub-ref]
+[Pub/Sub][cloud-pubsub] | stable | [`cloud.google.com/go/pubsub`][cloud-pubsub-ref]
[Spanner][cloud-spanner] | stable | [`cloud.google.com/go/spanner`][cloud-spanner-ref]
[Speech][cloud-speech] | stable | [`cloud.google.com/go/speech/apiv1`][cloud-speech-ref]
[Storage][cloud-storage] | stable | [`cloud.google.com/go/storage`][cloud-storage-ref]
