fix update_webhook arg

update.py

@@ -222,7 +222,7 @@ def update_webhooks():
       print("There are now", len(new_watched), "items in the watched list")
 
       api.update_webhook(
-          id=id2update, 
+          webhook_id=id2update, 
           url=webhook_url,
           watched=new_watched,
           domains=["discussion"],