Add m1 macos builds to the CI

[sobolevn]

It was just released: https://github.blog/changelog/2023-10-02-github-actions-apple-silicon-m1-macos-runners-are-now-available-in-public-beta/

Since m1 macs are very different from Intel macs, I think it might make sense to test both of them.

[sobolevn]

We need to figure out how billing works for this runner: https://docs.github.com/en/billing/managing-billing-for-github-actions/about-billing-for-github-actions#per-minute-rates

[hugovk]

https://github.blog/2023-10-02-introducing-the-new-apple-silicon-powered-m1-macos-larger-runner-for-github-actions/ says:

With today’s launch, our macOS larger runners will be priced at $0.16/minute for XL and $0.12/minute for large.

An M1 build takes ~4m 42s (5m billable time).

We've had ~200 builds in the past 24 hours (although some didn't need to build for Mac).

That's some ~$120/day.

[vstinner]

That's some ~$120/day.

IMO it's way too expensive for the PSF, compared to the cost of existing M1 and M2 buildbots:

• https://buildbot.python.org/all/#/workers/44 : "MacOS M1 worker"
• https://buildbot.python.org/all/#/workers/69 : "MacOS 14.0 M1 (ARM64) mac2.metal AWS instance"

I suggest to abandon this approach unless GitHub pricing changes. IMO buildbots are enough.