Use semver linting to protect against bad version bumps

Investigate using the third-party cargo plugin "cargo-semver-checks" on our Rust repos to verify that semver (based on the Rust interfaces) isn't violated. This should be done at crate publishing time, and potentially even before release by validating PRs that modify crate versions.

https://predr.ag/blog/toward-fearless-cargo-update/

https://github.com/obi1kenobi/cargo-semver-checks-action

This will require some configuration to work with our workspace tagging scheme.