[rush] Changes to pnpm-config should invalidate the lockfile

[Faithfinder]

Right now if I add an override and run rush update I need to additionally do something like adding and removing a dependency to a project to trigger the effects.

[iclanton]

It should, yeah. That should be easy to change. @dmichon-msft - would you mind putting something together?

[kenrick95]

This should be fixed by https://github.com/microsoft/rushstack/pull/4898