Using friendsofphp/php-cs-fixer instead of package fabpot/php-cs-fixe…

…r as that one has been abandoned.

composer.json

@@ -26,7 +26,7 @@
     "phpunit/phpunit": "~4.7|~5.3",
     "fzaninotto/faker": "~1.4",
     "mikey179/vfsStream": "~1.5",
-    "fabpot/php-cs-fixer": "~1.11",
+    "friendsofphp/php-cs-fixer": "~1.11",
     "guzzlehttp/guzzle": "~4.0|~5.0|~6.0",
     "symfony/console": "~2.3|~3.0",
     "symfony/process": "~2.3|~3.0"