dashboard not accessible from ipv6

Hi,

In the app.py, the listener listens by default only on ipv4 because is set to:

```bash
app.run(host='0.0.0.0', port=5000[...]
```

It is necessary to change this as follows for the interface to be accessible from IPv6:

```bash
app.run(host='::', port=5000[...]
```

Doing the following allows access via IPv6 but also via IPv4.