macOS 12 runner deprecation

[tueda]

We have resolved #536, but now unfortunately the macos-12 runner image is deprecated and will be unsupported by 3 December 2024 in GitHub Actions.

See also: actions/runner-images#10721

[jodavies]

It looks like things run through fine if we swap 12 for 13, so this should be straightforward.

[tueda]

Well, I am not sure if the binary built on a newer macOS will run on older versions (this applies also for 11 -> 12, though). And macOS 13 image will likely be deprecated one year later, but it is the last x64_64 runner image (unless on a paid plan). No one uses Intel Macs at that point??

[jodavies]

Maybe, "how many people actually use the pre-compiled binaries" is something we should have discussed at the workshop. Without the runners there is not really any choice regardless, if binaries should be provided via github. Keeping macos-13 is probably good if it is the last x86-64 macos runner, even if it indeed has to be removed in a year's time.

[jodavies]

Looks like we need to make this change now, the CI doesn't run on the macos-12 runners as of today.