Adjust the branch alias

Use `0.10-dev` as branch alias to keep that in sync with the phpstan version

Author: sascha-egerer

composer.json

@@ -6,7 +6,7 @@
     "prefer-stable": true,
     "extra": {
         "branch-alias": {
-            "dev-master": "0.9-dev"
+            "dev-master": "0.10-dev"
         }
     },
     "require": {