chore: bump to macos-13

[pfeerick]

GitHub is ending macos-12 support in December 2024, and is already throttling the build duration for this target as of July.

The macOS 12 runner image will be removed by December 3rd, 2024. To raise awareness of the upcoming removal, jobs using macOS 12 will temporarily fail during scheduled time periods defined below:

November 4, 9:00 AM - 7:00 PM EST
November 11, 9:00 AM - 7:00 PM EST
November 18, 9:00 AM - 7:00 PM EST
November 25, 9:00 AM - 7:00 PM EST

ref: actions/runner-images#10721

[philmoz]

That's annoying and is sure to upset a few users.

Might need to consider hosting custom builds somewhere.

[pfeerick]

So you're volunteering for that? :-P

While I do agree with the sentiment and agree that it will be frustrating, I'm not Apple, so don't set their policy of only supporting the current + last two major versions. It is more likely that we would get stuck needing to actually buy a Mac and running a self-hosted runner on it just to be sure we have access to the older setup as support for the older Mac versions is removed from availability.

FYI, this is not planned on being merged until 3rd of December ;)