Upgrade php-cs-fixer and use it in parallel (#6)

Author: maks-rafalko

app/.php-cs-fixer.dist.php

@@ -35,6 +35,7 @@
 
 use PhpCsFixer\Config;
 use PhpCsFixer\Finder;
+use PhpCsFixer\Runner\Parallel\ParallelConfigFactory;
 
 $header = \trim(
     <<<'TXT'
@@ -89,6 +90,7 @@
 ;
 
 return (new Config())
+    ->setParallelConfig(ParallelConfigFactory::detect())
     ->setRiskyAllowed(true)
     ->setRules([
         '@PHP71Migration' => true,