Composer branch alias

Author: yann-eugone

composer.json

@@ -39,7 +39,8 @@
     "minimum-stability": "stable",
     "extra": {
         "branch-alias": {
-            "dev-master": "3.x-dev"
+            "dev-3.x": "3.x-dev",
+            "dev-2.x": "2.x-dev"
         }
     }
 }