Move cs-fixer to dev dependencies

Author: akondas

composer.json

@@ -11,10 +11,10 @@
     ],
     "require": {
         "php": "^8.1",
-        "react/http": "^0.8.1",
-        "friendsofphp/php-cs-fixer": "^3.8"
+        "react/http": "^0.8.1"
     },
     "require-dev": {
+        "friendsofphp/php-cs-fixer": "^3.8",
         "phpunit/phpunit": "^9.5",
         "phpstan/phpstan": "^1.6"
     },