Improve PHP-CS-Fixer configuration (#225)

Author: sanmai

.php-cs-fixer.dist.php

@@ -1,5 +1,14 @@
 <?php
 
+/*
+ * This file is part of the Liquid package.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @package Liquid
+ */
+
 $header = <<<'EOF'
 This file is part of the Liquid package.
 
@@ -11,6 +20,7 @@
 
 $config = new PhpCsFixer\Config();
 $config
+	->setParallelConfig(PhpCsFixer\Runner\Parallel\ParallelConfigFactory::detect())
 	->setRiskyAllowed(true)
 	->setRules([
 		'@PSR2' => true,
@@ -40,6 +50,7 @@
 	->setFinder(
 		PhpCsFixer\Finder::create()
 		->in(__DIR__)
+		->append([__FILE__])
 	)
 ;