FODS support?

### Issue
I'd like to open a Flat XML ODF Spreadsheet (.fods) file but it currently doesn't work:
```
TypeError: /path/to/file.fods is not an Roo::OpenOffice file
```

FODS support would be awesome because it's pure text and thus much more Git friendly. Is this something planned?

### System configuration
**Roo version**: 2.10.1

**Ruby version**: 3.3.0