- This will give some information to users of `brew bump` that they
  should keep the version of the formula in sync with other formulae.
- A future enhancement is actually making the bumping of the "related"
  formulae automatic with `--open-pr`. But for now, telling people so
  that they don't have to wait until `brew audit` fails either locally
  or in CI at a later stage is a good start.

- This way we can use them in the audit and in `bump`.