update branch alias

Author: xabbuh

composer.json

@@ -35,7 +35,7 @@
     "extra": {
         "branch-alias": {
             "1.x-dev": "1.2.x-dev",
-            "2.x-dev": "2.1.x-dev",
+            "2.x-dev": "2.2.x-dev",
             "dev-master": "2.1.x-dev"
         }
     }