Prevent unsuccessful response

[mikaelpopowicz]

Hello @freekmurze, thanks for the package.

This adds an option to throw an exception when response is unuccessful :

try {
    Browsershot::url('https://example.com/404')
        ->preventUnsuccessfulResponse()
        ->save($targetPath);
} catch (UnsuccessfulResponse $exception) {
    // ...
}

Have a good day.

[freekmurze]

Thanks!