Tests failing w/ most recent urllib3 release

[jsstevenson]

The most recent urllib3 release checks for a response object property in a logging statement that the vcrpy response mock didn't declare. This makes tests fail.

• this commit makes no changes against main except for a small rearrangement in pyproject.toml so as to trigger cache invalidation in GH actions. tests fail. https://github.com/ga4gh/vrs-python/actions/runs/12472767000
• pinning the previous urllib3 version fixes it: https://github.com/ga4gh/vrs-python/actions/runs/12472815878
• corresponding issue in vcrpy: missing request.version_string attribute with urllib3 == 2.3.0  kevin1024/vcrpy#888

[jsstevenson]

Temp fix in #473. This issue should stay open until the VCRPy fix is merged and we can pin the release with the fix.