firmwareVersion endpoint returns a 404

My Nanoleaf Aurora is on firmware version 3.3.4. The firmware version is not available on the endpoint this library checks for, instead it seems the only way to retrieve it is via the global getter that returns all of the device information.

```
>>> a
<Aurora(192.168.1.19)>
>>> a.firmware
Error 404: Resource not found! (192.168.1.19)
>>> a.info["firmwareVersion"]
'3.3.4'
```