Update readme with supported versions.

Author: TavoNiievez

readme.md

@@ -9,7 +9,7 @@ A Codeception module for Laravel framework.
 
 ## Requirements
 
-* `Laravel 6` or higher.
+* `Laravel 8` or higher, as per the [Laravel supported versions](https://laravel.com/docs/master/releases#support-policy).
 * `PHP 7.4` or higher.
 
 ## Installation