Not PHP 7.2 compliant with the last version of Slim 2

[maidmaid]

A warning is triggered by PHP 7.2 with the last version of Slim 2 :

Declaration of Slim\Extras\Views\Twig::render($template) should be compatible with Slim\View::render($template, $data = NULL) in vendor/slim/extras/Slim/Extras/Views/Twig.php

cf https://github.com/codeguy/Slim-Extras/blob/a35bc4d15a7efc5e938d8f5fea6b8382912892d5/Views/Twig.php#L94 cf https://github.com/slimphp/Slim/blob/7d3308bb8b41238941c0cbf549ef103c1bd69a30/Slim/View.php#L268