Add missing dev requirement

Author: JamesDPC

composer.json

@@ -22,6 +22,7 @@
         "unclecheese/display-logic": "^2"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.5"
+        "phpunit/phpunit": "^9.5",
+        "friendsofphp/php-cs-fixer": "^3"
     }
 }