[Request] For FailedNotification to have twilio exception error code

[jkatz50]

Currently, only the error message is passed back when twilio fails to send. It would be cool to be able to get the twilio error code (or whole exception) for more consistent handling: https://www.twilio.com/docs/api/errors/reference

This is how the event is currently fired: https://github.com/laravel-notification-channels/twilio/blob/master/src/TwilioChannel.php#L58-L62

} catch (Exception $exception) {
    $this->events->fire(
        new NotificationFailed($notifiable, $notification, 'twilio', ['message' => $exception->getMessage()])
     );
}

[gregoriohc]

This has been added on release 2.0.2