Fix missing comma after merge

Author: stephangroen

composer.json

@@ -21,7 +21,7 @@
         "ext-json": "*"
     },
     "require-dev": {
-        "phpstan/phpstan": "^2.1"
+        "phpstan/phpstan": "^2.1",
         "phpunit/phpunit": "^9.6"
     },
     "autoload": {