Add caching action/example?

[zkat]

GHA supports caching now! It would be awesome to have either an example or a wrapper action for dealing with dependency builds and maybe even tooling installs?

[svartalf]

I still had not found time to test it, but this Rust example could be a starting point maybe?

Also, I would really appreciate any PRs with examples, as my schedule is a bit tight at the moment.