* Fix supervisor ping URL
In the current version I had to ping `http://<host>/supervisor/ping`, instead of `http://<host>/ping` as implied by the docs.
```
$ curl -sSL -H 'Authorization: Bearer <TOKEN>' 'http://homeassistant.local/ping'
404: Not Found
$ curl -sSL -H 'Authorization: Bearer <TOKEN>' 'http://homeassistant.local/supervisor/ping'
{"result": "ok", "data": {}}
```
* Use 'supervisor' as host name
Co-authored-by: Franck Nijhof <frenck@frenck.nl>
Co-authored-by: Franck Nijhof <frenck@frenck.nl>
