parallelisation issues and platform support issues on circleci is becoming ever more painful. some goals:

• need better platform support for pre-1.0 stability guarantees #508 (want windows build working, but only got mac so far)
• need more than parallelisation factor of 1 from circleci (they nerfed it quite hard) so we can run more tests (20 from github actions)
• need better caching to speed up workflows (15min cycles are painful) - linked pr seems ok
• maybe ditch musl (only used for integration test to shove into docker, do whatever is fastest)
• serve as an easy to understand example for users of kube Document recommended deployment environment #332

@kazk, I know you started on this in https://github.com/clux/kube-rs/blob/use-github-actions/.github/workflows/ci.yml from #510 (after discussion points in #508 (comment)). Am happy to resume that unless it ties in majorly with any potential kube-test plans in #382.