korzo

I tried several invalid ISBNs, but all pass the validation in v3.0.3. ```php $isbn = new \Isbn\Isbn(); var_dump($isbn->validation->isbn('7640108702869')); var_dump($isbn->validation->isbn('5055300330994')); var_dump($isbn->validation->isbn('5017239196706')); var_dump($isbn->validation->isbn('0090204645565')); var_dump($isbn->validation->isbn('4013594529877')); ``` show 5x true.