fix(pubsub): increase streaming pull timeout (googleapis#8345)

* fix(pubsub): increase streaming pull timeout

Pub/Sub streaming pull timeout should be increased to match the values in https://github.com/googleapis/googleapis/blob/master/google/pubsub/v1/pubsub_grpc_service_config.json

* Increase RPC timeout values in subscriber config

Author: hongalex

handwritten/pubsub/src/v1/subscriber_client_config.json

@@ -43,10 +43,10 @@
           "initial_retry_delay_millis": 100,
           "retry_delay_multiplier": 4,
           "max_retry_delay_millis": 60000,
-          "initial_rpc_timeout_millis": 60000,
+          "initial_rpc_timeout_millis": 180000,
           "rpc_timeout_multiplier": 1,
-          "max_rpc_timeout_millis": 60000,
-          "total_timeout_millis": 600000
+          "max_rpc_timeout_millis": 1800000,
+          "total_timeout_millis": 1800000
         }
       },
       "methods": {
@@ -91,7 +91,7 @@
           "retry_params_name": "default"
         },
         "StreamingPull": {
-          "timeout_millis": 900000,
+          "timeout_millis": 1800000,
           "retry_codes_name": "deadline_exceeded_resource_exhausted_aborted_internal_unavailable",
           "retry_params_name": "693222d32e887d96c8faeadca469f7763ccda85a"
         },