add branch alias for 0.15.0 [skip ci]

Author: troosan

composer.json

@@ -77,7 +77,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-develop": "0.15.0-dev"
+            "dev-master": "0.15.0-dev"
         }
     }
 }