cibuildwheel: While cibuildwheel can build CPython 3.8 universal2/arm64 wheels, we cannot test the arm64 part of them, even when running on an Apple Silicon machine. This is because we use the x86_64 installer of CPython 3.8. See the discussion in https://github.com/pypa/cibuildwheel/pull/1169 for the details. To silence this warning, set `CIBW_TEST_SKIP: "cp38-macosx_*:arm64"`.

The macos-latest label will migrate to macOS 15 beginning August 4, 2025. For more information see https://github.com/actions/runner-images/issues/12520