chore: limit Cirrus CI usage

[mayeut]

New usage limits are now enforced on Cirrus CI: https://cirrus-ci.org/faq/#are-there-any-limits
Limit runs to the minimum.

[joerick]

Thanks. It does kinda suck that this takes out our only arm64 mac CI run, but I can't see a way around it right now. GHA and Circle arm64 runners are paid, I think.

[Czaki]

@joerick I see that circle.ci has option to extend support of opensource. did you try to contact here: https://circleci.com/talk-to-us/?source-button=Request%20early%20access%20-%20Open%20Source%20usage%20plan

Did we know which platform may be cheapest (and if it will be ok for you to apply for some grant for cover such option?)?

[joerick]

@Czaki, good point. Actually, that reminds me that we already have some kind of open-source exemption with CircleCI. So it would be worth trying their existing m1 runners, we might already have access.

[henryiii]

Could be worth asking if we need something for any CI provider; we are providing them more potential customers by supporting them, after all.