Add CITATION.cff file for easier repo citation (#498)
Add CITATION.cff file for easier repo citation (#498)

* Add CITATION.cff file for easier repo citation

GitHub has added native support of the CITATION.cff file format, which
provides a nice way to generate a citation for a software repository.

This adds in a basic citation.cff file, which can be updated as
necessary.

* Include foyer reference and clean up names

* Update preferred citation and message.

* update format

* fix schema issue

Co-authored-by: Co Quach <a2f41c5129449aab4dc24a8ff0544352b5fb9f1d@gmail.com>
mosdef-hub/foyer,mosdef-hub/foyer