fix(crc32c): Drop support for Python 3.8 and 3.9

[chalmerlowe]

This PR updates `google-crc32c` to establish Python 3.10 as the minimum supported version, dropping support for Python 3.7, 3.8, and 3.9.

Changes

• Configuration: Updated `setup.cfg` and `pyproject.toml` to require Python 3.10+ and remove references to Python 3.8 and 3.9.
• Nox: Updated `noxfile.py` to remove Python 3.7, 3.8, and 3.9 from unit test versions.
• Documentation: Updated `README.md` to reflect supported Python versions and published wheels.

Note: Verification tests were skipped locally due to environment issues with building the C library in the Docker container, but changes are strictly metadata and configuration!

Fixes internal issue: http://b/482126936 🦕

[gemini-code-assist]

Code Review

This pull request drops support for Python versions below 3.10, updating the README, Noxfile, pyproject.toml, and setup.cfg accordingly. A review comment identifies that Python 3.13 and 3.14 are missing from the classifiers in setup.cfg, which should be added to ensure consistency with the documentation and test matrix.

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packages/google-crc32c/setup.cfg (32-33)

The classifiers section in setup.cfg is missing entries for Python 3.13 and 3.14. Since these versions are explicitly listed as supported in the README.md and are included in the noxfile.py test matrix, they should be added to the metadata to ensure consistency and to correctly signal support on PyPI.