Bump test version of numcodecs

[dstansby]

This bumps the test version of numcodecs to 0.13.0, and fixes a test where the output changed with 0.13.0. Along the way I made the test a bit simpler to avoid having to deal with multi-line strings.

TODO:

• GitHub Actions have all passed
• Test coverage is 100% (Codecov passes)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.98%. Comparing base (35e8106) to head (12ef3e5).
Report is 364 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2114   +/-   ##
=======================================
  Coverage   99.98%   99.98%           
=======================================
  Files          38       38           
  Lines       14711    14714    +3     
=======================================
+ Hits        14709    14712    +3     
  Misses          2        2           

Files with missing lines	Coverage Δ
zarr/tests/test_meta.py	100.00% <100.00%> (ø)

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[jhamman]

Thanks @dstansby!