feat(CI): Speed up cs:check with parallelism

Signed-off-by: Joas Schilling <coding@schilljs.com>

.php-cs-fixer.dist.php

@@ -8,9 +8,11 @@ declare(strict_types=1);
 require_once './vendor-bin/cs-fixer/vendor/autoload.php';
 
 use Nextcloud\CodingStandard\Config;
+use PhpCsFixer\Runner\Parallel\ParallelConfigFactory;
 
 $config = new Config();
 $config
+	->setParallelConfig(ParallelConfigFactory::detect())
 	->getFinder()
 	->ignoreVCSIgnored(true)
 	->exclude('config')