Auto-populate author list in `CITATION.cff` from all-contributors data

[matt-graham]

See https://github.com/astro-informatics/s2fft/pull/236#issuecomment-2404449219

In summary ideally we should automatically update the authors field in CITATION.cff file based on the contributors listed in .all-contributorsrc potentially basing this on something like this script which does something similar but using a different (YAML) source file.