Update macOS runner for CI

[capnkenny]

Please check if the PR fulfills these requirements

• [X] The commit message follows our guidelines
• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Documentation has been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...) Updates the runner for CI to use the latest compatible macOS available (without further code modifications).

Is there an open issue that this resolves? If so, please link it here. Fixes #602

[github-actions[bot]]

Test Results

   10 files  +    4     10 suites  +4   6m 1s :stopwatch: + 3m 15s   693 tests ±    0    693 :white_check_mark: ±    0  0 :zzz: ±0  0 :x: ±0  6 930 runs  +2 772  6 930 :white_check_mark: +2 772  0 :zzz: ±0  0 :x: ±0 

Results for commit 883f0cbf. ± Comparison against base commit 2e3668ec.

:recycle: This comment has been updated with latest results.