chore: update branch-alias (#5030)

Author: dunglas

composer.json

@@ -143,7 +143,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-main": "3.0.x-dev"
+            "dev-main": "3.1.x-dev"
         },
         "symfony": {
             "require": "^6.1"