feat[rio-pmtiles]: allow min and/or max zoom to be omitted when specifying zoom levels

[JaffaKetchup]

This means, for example, the user can specify a min zoom level and still leave the max to be auto calculated.

For example:

• 16.. generates 16-auto
• .. generates 0-auto
• ..16 generates 0-16

[bdon]

Thanks for the enhancement, can you add a test like the one in https://github.com/protomaps/PMTiles/blob/main/python/rio-pmtiles/tests/test_cli.py#L78 ?