Update php-cs-fixer, change to symfony rule set

Author: samuelwei

.php-cs-fixer.php

@@ -0,0 +1,22 @@
+<?php
+
+// Invoke the config easily with `php-cs-fixer fix`
+
+$finder = \PhpCsFixer\Finder::create()
+    ->files()
+    ->name('*.php')
+    ->in(__DIR__ . '/src')
+    ->in(__DIR__ . '/tests');
+
+$config = new PhpCsFixer\Config();
+
+return $config
+    ->setUsingCache(false)
+    ->setRules([
+        '@Symfony' => true,
+        '@Symfony:risky' => true,
+        'yoda_style' => false,
+        'single_line_throw' => false,
+    ])
+    ->setRiskyAllowed(true)
+    ->setFinder($finder);

.php_cs

@@ -1,5 +1,5 @@
 {
     "require": {
-        "friendsofphp/php-cs-fixer": "2.*"
+        "friendsofphp/php-cs-fixer": "3.*"
     }
 }