macOS 15 runner is available

[Ryan Carsten Schmidt]

> On Sep 30, 2024, at 18:47, Mark E Anderson wrote:
> 
> Github seems to have a macOS 15 runner in beta, which might help out on our quest to squash macOS 15 bugs. Although, I have noticed the CI can be a little fickle when doing something big like qt.

I haven't set up the macOS 15 arm64 buildbot machine yet. That means CI would have to build not just the port being changed but also all of its dependencies which could exceed the allotted build time and make scarce CI resources unavailable to others.