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:

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

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.98%. Comparing base (35e8106) to head (12ef3e5). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2114 +/- ## ======================================= Coverage 99.98% 99.98% ======================================= Files 38 38 Lines 14711 14714 +3 ======================================= + Hits 14709 14712 +3 Misses 2 2 ``` | [Files](https://app.codecov.io/gh/zarr-developers/zarr-python/pull/2114?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zarr-developers) | Coverage Δ | | |---|---|---| | [zarr/tests/test\_meta.py](https://app.codecov.io/gh/zarr-developers/zarr-python/pull/2114?src=pr&el=tree&filepath=zarr%2Ftests%2Ftest_meta.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zarr-developers#diff-emFyci90ZXN0cy90ZXN0X21ldGEucHk=) | `100.00% <100.00%> (ø)` | |

[jhamman]

Thanks @dstansby!