Semver Checks + Changelog dry run actions in CI

[makspll]

I don't want to keep having to wrestle release-plz commits onto main before seeing what they will do.

I'd like to have a dry run action for release-plz or at least git cliff that will allow developing that config before merging to main.

I would also like to run cargo-semver-checks on each PR, and fail the PR if it's conventional commit doesn't cover a breaking change, I want to have better breaking change hygiene, and automatically collect migration guides eventually