fix(ci): use latest 3.x python version

[diranged]

Bug: https://github.com/diranged/oz/actions/runs/12802274037/job/35693092033?pr=355

The Github Team has changed ubuntu-latest to point to 24.04 now - and there is no version of Python 3.7 for 24.04 on the x64 arch..

[coveralls]

Pull Request Test Coverage Report for Build 12891668113

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 38.51%

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Totals
Change from base Build 12677085925:	0.0%
Covered Lines:	1091
Relevant Lines:	2833

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💛 - Coveralls