Use `cargo-semver-checks` to prevent accidental breaking changes.

[jswrenn]

We should consider using cargo-semver-checks-action to prevent accidental breaking changes.

[DavidCoy77]

Hi! I'd love to get started contributing to Rust, but I'd need a little help getting started since this would be my first ever GitHub contribution. I've tinkered around in RustRover so I'm eager to get to work if you're willing to help me out. Thanks!

[Philippe-Cholet]

@DavidCoy77 I don't know if #784 resolves this issue but Owen-CH-Leung is working on it.