style: format code with PHP CS Fixer

This commit fixes the style issues introduced in 7569d9c according to the output
from PHP CS Fixer.

Details: #280

src/Response.php

@@ -2,21 +2,24 @@
 
 namespace GuiBranco\Pancake;
 
-class Response {
-    public static function success($data, $message = 'Success') {
+class Response
+{
+    public static function success($data, $message = 'Success')
+    {
         return [
             'status' => 'success',
             'message' => $message,
             'data' => $data
         ];
     }
 
-    public static function error($code, $message, $details = []) {
+    public static function error($code, $message, $details = [])
+    {
         return [
             'status' => 'error',
             'code' => $code,
             'message' => $message,
             'details' => $details
         ];
     }
-}
+}