Add 'header_comment' rule

Author: smnandre

.php-cs-fixer.dist.php

@@ -4,11 +4,21 @@
     exit(0);
 }
 
+$fileHeaderComment = <<<'EOF'
+This file is part of the Symfony package.
+
+(c) Fabien Potencier <[email protected]>
+
+For the full copyright and license information, please view the LICENSE
+file that was distributed with this source code.
+EOF;
+
 return (new PhpCsFixer\Config())
     ->setRules([
         '@PHPUnit75Migration:risky' => true,
         '@Symfony' => true,
         '@Symfony:risky' => true,
+        'header_comment' => ['header' => $fileHeaderComment],
     ])
     ->setRiskyAllowed(true)
     ->setFinder(