Added conflict for messenger recipe

Author: HeahDude

symfony/messenger/4.1/manifest.json

@@ -5,5 +5,8 @@
     "env": {
         "#1": "MESSENGER_TRANSPORT_DSN=amqp://guest:guest@localhost:5672/%2f/messages"
     },
-    "aliases": ["messenger"]
+    "aliases": ["messenger"],
+    "conflict": {
+        "symfony/framework-bundle": "<4.1"
+    }
 }