Support running changie in a custom directory

[wjam]

It would be useful to be able to run changie within custom directories, such as if actions/checkout was run with path specified.

[miniscruff]

I am curious as to your layout for this, are you using a mono repo? But either way it seems like a fair request.

[wjam]

It's more inter-repository. Releasing a thing in one repository causes a workflow to raise a PR against another repository with the new version (which uses changie to manage its release notes)