Possible tweak to converters - bumping the ome-zarr version

[seankmartin]

There's nothing major here but left a few comments on #6. The only one that isn't just a refactoring or some links in case useful for reference, is to use ome-zarr 0.5 with zarr v3, not ome-zarr 0.4 with zarr v2 (or at least to have the option to choose the version)