`cargo release` for releasing the coreutils

[tertsdiepraam]

Instead of our custom script for tagging and publishing releases, I think we should use cargo release (or some other similar tool). However, I think there's a small problem with cargo release at the moment which is that it cannot work around the rate limits of crates.io. They only do a check that you're not going to hit the rate limit, but of course we will always hit the rate limit with ~100 crates.

[tertsdiepraam]

There is a possible workaround for the rate limit, which is to set the PUBLISH_GRACE_SLEEP[^1] environment variable to a high enough value to not trigger the limit. I think that allows us to use cargo release for publishing crates.

[^1]: Documented at https://github.com/crate-ci/cargo-release/blob/master/docs/reference.md