chore: set parallel config on php-cs-fixer (#251)

Author: rancoud

.php-cs-fixer.php

@@ -65,4 +65,5 @@
 return $config->setFinder($finder)
     ->setRules($rules)
     ->setRiskyAllowed(true)
-    ->setUsingCache(true);
+    ->setUsingCache(true)
+    ->setParallelConfig(PhpCsFixer\Runner\Parallel\ParallelConfigFactory::detect());