Re: [PATCH v2] github-ci: update macos jobs to macos-15

Patrick Steinhardt [off-list ref] writes:

So personally I'd keep it at the explicit versions for now so that both
are in sync. We have to bump versions for one of them anyway, so we
should make sure to just bump them both at the same time going forward.

... or deliberately make them diverge for more variety.  I'll drop
the v3 patch and use v2.

Thanks.