Add citation file

[scrasmussen]

For the release it would be nice to:

• add a CITATION.cff file to the repository. This adds a Cite this repository button to the GitHub repo and helps make citing easier. This citation file will also automatically point to the most recent DOI version of a software release. Use existing Zenodo DOI and point to the latest release, so the citation file will always be up-to-date.

  Example

[scrasmussen]

Citation file commits have been merged into main