Would you consider accepting enforce_api_boundary as an alternative to enforce_privacy? #97

Hi all!

I have been spinning the wheels on packwerk and love it so far!

Regarding privacy - when listing privacy constraints by constant, I would like to list the public files in the config so any new constants are private by default. Right now I can only use enforce_privacy which will make new constants public by default. With the new name I propose, enforce_api_boundary, the behavior of true could stay the same.

Is this something you would accept a PR for?