Update php-cs-fixer to 2.7

Author: Nico Stapelbroek

composer.json

@@ -28,7 +28,7 @@
  "sebastian/version": "^1.0.3|^2.0",
  "mikey179/vfsStream": "^1.2",
  "lapistano/proxy-object": "dev-master#d7184a479f502d5a0f96d0bae73566dbb498da8f",
- "friendsofphp/php-cs-fixer": "^1.12"
+ "friendsofphp/php-cs-fixer": "^2.7|^1.12"
  },
 
  "autoload": {