Update PHP CS Fixer config file

.php_cs.dist

@@ -1,15 +1,14 @@
 <?php
 
-return Symfony\CS\Config\Config::create()
-    ->setUsingLinter(false)
-    ->setUsingCache(true)
-    ->fixers(array(
-        'long_array_syntax',
-        'php_unit_construct',
-        'php_unit_dedicate_assert',
+return PhpCsFixer\Config::create()
+    ->setRules(array(
+        '@Symfony' => true,
+        '@Symfony:risky' => true,
+        'array_syntax' => array('syntax' => 'long'),
     ))
-    ->finder(
-        Symfony\CS\Finder\DefaultFinder::create()
+    ->setRiskyAllowed(true)
+    ->setFinder(
+        PhpCsFixer\Finder::create()
             ->in(__DIR__)
             ->exclude(array(
                 // directories containing files with content that is autogenerated by `var_export`, which breaks CS in output code