Fix Exception Handler broken for Laravel 8

[antonioribeiro]

Description

As Twill is replacing (by default) the Laravel Exception Handler, on Laravel 8 this has some bad outcomes. As the handler now uses the App\Exceptions\Handler::register() method to register new closure handlers, this method is never called by Twill and this would never work:

    /**
     * Register the exception handling callbacks for the application.
     *
     * @return void
     */
    public function register()
    {
        $this->renderable(function (MyException $e) {
            return response()->view('errors.exception', [], 500);
        });
    }

Solution

Instead of extending Illuminate\Foundation\Exceptions\Handler, we can probably extend App\Exceptions\Handler as this class will always exist on new Laravel applications and it also extends Laravel's Exception handler.