rust-miniscript workflow notes

We are attempting to run max 20 parallel jobs using GitHub actions (usage limit for free tier).

ref: https://docs.github.com/en/actions/learn-github-actions/usage-limits-billing-and-administration

The minimal/recent lock files are handled by CI (rust.yml).

Jobs

Run from rust.yml unless stated otherwise. Total 11 jobs.

1. Stable - minimal
2. Stable - recent
3. Nightly - minimal
4. Nightly - recent
5. MSRV - minimal
6. MSRV - recent
7. Lint
8. Docs
9. Docsrs
10. Bench
11. Format
12. Int-tests
13. Embedded