Sync with zarr 3 beta

[mpiannucci]

This syncs the zarr3 wrapper with the latest zarr beta.

TODO:

• Unit tests and/or doctests in docstrings
• Tests pass locally
• Docstrings and API docs for any new/modified user-facing classes and functions
• Changes documented in docs/release.rst
• Docs build locally
• GitHub Actions CI passes
• Test coverage to 100% (Codecov passes)

[jhamman]

@normanrz - we (@mpiannucci and the crew at Earthmover) are interested in helping finish off #524. Do you have the bandwidth to review some work in this space?

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 91.29%. Comparing base (b75e41e) to head (d01669b).
Report is 1 commits behind head on zarr3-codecs.

Files with missing lines	Patch %	Lines
numcodecs/zarr3.py	50.00%	6 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           zarr3-codecs     #597      +/-   ##
================================================
- Coverage         94.31%   91.29%   -3.02%     
================================================
  Files                61       61              
  Lines              2584     2586       +2     
================================================
- Hits               2437     2361      -76     
- Misses              147      225      +78     

Files with missing lines	Coverage Δ
numcodecs/zarr3.py	57.71% <50.00%> (+0.48%)	⬆️

... and 3 files with indirect coverage changes