Generating an escrow-packet fails

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/storage_administration_guide/ch-volumekey

Attempting to generate an escrow-packet as documented at the above link fails with the following error:

```
sudo volume_key --save ./luks.img --output ./escrow-packet

volume_key: Error opening `./luks.img': Error getting information about volume `./luks.img': Invalid argument
```

The exact same command works on Fedora Workstation 38.

To replicate the issue, do the following:
- On Ubuntu 22.04 (haven't tested other releases)

- Install `volume-key` package

- Generate a LUKS encrypted volume
```
# Pre-allocate a 1GB volume
sudo fallocate -l 1GB ./luks.img

sudo cryptsetup luksFormat ./luks.img
# Follow prompts to setup the volume with a passphrase
```

- Try to generate the escrow-packet
```
sudo volume_key --save ./luks.img --output ./escrow-packet
```