What to do in the case of the error: "Subvolume has no UUID" ?

Hi !,

I have this error : `ERROR: Skipping subvolume "/home": subvolume has no UUID`
I effectively have no UUID (as described in the [FAQ](https://digint.ch/btrbk/doc/faq.html))

`btrfs subvolume show`:
```
/
Name:
UUID: -
Parent UUID: -
...
```

This is my config
```
volume /
target xxx.xxx.xxx.xxx:/media/backup_pc
subvolume /home
snapshot_name home
snapshot_dir /home/btrbk_snapshots

```

How can I give a new UUID to my btrfs volume ?