Passing the timeout to the subscribe Stub

The timeout parameter is not used in this function, so we dont have a way to set timeout for the subscription. This change will fix that.

pygnmi/client.py

@@ -1002,7 +1002,7 @@ def subscribe(
             gnmi_message_request = self._build_subscriptionrequest(subscribe)
             debug_gnmi_msg(self.__debug, gnmi_message_request, "gNMI request")
 
-        return self.__stub.Subscribe(self.__generator(gnmi_message_request), metadata=self.__metadata)
+        return self.__stub.Subscribe(self.__generator(gnmi_message_request), metadata=self.__metadata, timeout=timeout)
 
     def subscribe2(self, subscribe: dict, target: str = None, extension: list = None):
         """