Source based coverage was stabilized

[Shatur]

With Rust 1.60 source based coverage was stabilized. So starting with this version instrument-coverage now in stable book. Could you add support for Rust 1.60 by checking the available version?

[Swatinem]

This action also depends on rust-lang/cargo#9427 currently, which is still not stabilized. Though I might as well push for it to get stabilized eventually.

[Swatinem]

I have now officially deprecated my action in favor of https://github.com/taiki-e/cargo-llvm-cov.
That solution will work on stable, and allows opting into nightly doctests if you care about those.