[Bug]: Min req tests failing on import zarr

[rly]

What happened?

The nightly macos-python3.7-minimum tests have been failing for 2 days. See stacktrace.

Steps to Reproduce

See https://github.com/hdmf-dev/hdmf-zarr/actions/runs/5301947163/jobs/9596558206

Traceback

==================================== ERRORS ====================================
________________ ERROR collecting tests/unit/test_io_convert.py ________________
ImportError while importing test module '/Users/runner/work/hdmf-zarr/hdmf-zarr/tests/unit/test_io_convert.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
../../../hostedtoolcache/Python/3.7.17/x64/lib/python3.7/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/unit/test_io_convert.py:40: in <module>
    from hdmf_zarr.backend import (ZarrIO,
src/hdmf_zarr/__init__.py:1: in <module>
    from .backend import ZarrIO
src/hdmf_zarr/backend.py:12: in <module>
    import zarr
.tox/py37-minimum/lib/python3.7/site-packages/zarr/__init__.py:2: in <module>
    from zarr.codecs import *
.tox/py37-minimum/lib/python3.7/site-packages/zarr/codecs.py:2: in <module>
    from numcodecs import *
.tox/py37-minimum/lib/python3.7/site-packages/numcodecs/__init__.py:32: in <module>
    from numcodecs.bz2 import BZ2
.tox/py37-minimum/lib/python3.7/site-packages/numcodecs/bz2.py:1: in <module>
    import bz2 as _bz2
../../../hostedtoolcache/Python/3.7.17/x64/lib/python3.7/bz2.py:19: in <module>
    from _bz2 import BZ2Compressor, BZ2Decompressor
E   ModuleNotFoundError: No module named '_bz2'
__________________ ERROR collecting tests/unit/test_zarrio.py __________________
ImportError while importing test module '/Users/runner/work/hdmf-zarr/hdmf-zarr/tests/unit/test_zarrio.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
../../../hostedtoolcache/Python/3.7.17/x64/lib/python3.7/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/unit/test_zarrio.py:12: in <module>
    from tests.unit.base_tests_zarrio import (BaseTestZarrWriter,
tests/unit/base_tests_zarrio.py:13: in <module>
    import zarr
.tox/py37-minimum/lib/python3.7/site-packages/zarr/__init__.py:2: in <module>
    from zarr.codecs import *
.tox/py37-minimum/lib/python3.7/site-packages/zarr/codecs.py:2: in <module>
    from numcodecs import *
.tox/py37-minimum/lib/python3.7/site-packages/numcodecs/__init__.py:32: in <module>
    from numcodecs.bz2 import BZ2
.tox/py37-minimum/lib/python3.7/site-packages/numcodecs/bz2.py:1: in <module>
    import bz2 as _bz2
../../../hostedtoolcache/Python/3.7.17/x64/lib/python3.7/bz2.py:19: in <module>
    from _bz2 import BZ2Compressor, BZ2Decompressor
E   ModuleNotFoundError: No module named '_bz2'

Operating System

Linux

Python Executable

Conda

Python Version

3.7

Package Versions

No response

Code of Conduct

• I agree to follow this project's Code of Conduct
• Have you checked the Contributing document?
• Have you ensured this bug was not already reported?

[rly]

This appears to be due to the CI-based installation of Python 3.7.17 missing the _bz2 module. See actions/setup-python#682

This is a CI/environment issue and not a problem of hdmf-zarr. It will hopefully be resolved, but even if not, Python 3.7 is near end of life and we can drop 3.7 support to avoid this issue.