Merge pull request #1080 from BahmanMD/Update-Extension.tpl.php

[make:twig-extension] reference twig 3.x docs in generated extension

Author: jrushlow

src/Resources/skeleton/twig/Extension.tpl.php

@@ -13,7 +13,7 @@ public function getFilters(): array
         return [
             // If your filter generates SAFE HTML, you should add a third
             // parameter: ['is_safe' => ['html']]
-            // Reference: https://twig.symfony.com/doc/2.x/advanced.html#automatic-escaping
+            // Reference: https://twig.symfony.com/doc/3.x/advanced.html#automatic-escaping
             new TwigFilter('filter_name', [$this, 'doSomething']),
         ];
     }