Include Cargo.lock in package checks.

Include Cargo.lock in package checks.

This includes `Cargo.lock` in the git dirty check. It explicitly excludes
`Cargo.lock` as an untracked file, since it is not relevant for the dirty check;
it is only checked if it is committed to git.

This also adds `Cargo.lock` to the "did anything modify this" check during
verification. I don't see a reason to exclude it (particularly since ephemeral
workspaces do not save the lock file).

Also add "Archiving: Cargo.lock" to the verbose output.