Explicit Messenger bus configuration (#1298)

Author: priyadi

symfony/webapp-pack/1.0/config/packages/messenger.yaml

@@ -15,6 +15,11 @@ framework:
             failed: 'doctrine://default?queue_name=failed'
             # sync: 'sync://'
 
+        default_bus: messenger.bus.default
+
+        buses:
+            messenger.bus.default: []
+
         routing:
             Symfony\Component\Mailer\Messenger\SendEmailMessage: async
             Symfony\Component\Notifier\Message\ChatMessage: async