Remove php-cs-fixer from the require-dev dependencies

Author: Nico Stapelbroek

composer.json

@@ -27,8 +27,7 @@
  "phpunit/phpunit": "^4.8|^5.0",
  "sebastian/version": "^1.0.3|^2.0",
  "mikey179/vfsStream": "^1.2",
- "lapistano/proxy-object": "dev-master#d7184a479f502d5a0f96d0bae73566dbb498da8f",
- "friendsofphp/php-cs-fixer": "^2.7|^1.12"
+ "lapistano/proxy-object": "dev-master#d7184a479f502d5a0f96d0bae73566dbb498da8f"
  },
 
  "autoload": {