Update branch-alias

Author: natanfelles

composer.json

@@ -68,5 +68,10 @@
         "optimize-autoloader": true,
         "preferred-install": "dist",
         "sort-packages": true
+    },
+    "extra": {
+        "branch-alias": {
+            "dev-master": "3.x-dev"
+        }
     }
 }