DOCS: add a doi so this implementation can be cited in papers

[antoinecollet5]

This great work definitely deserves a DOI and a proper way to be referenced. It can be done very easily on https://zenodo.org/.

Or even better, but a bit more time consuming, write an associated paper: https://joss.theoj.org/

[tommyod]

Thanks for the suggestion @antoinecollet5 ! We'll probably look into this once the API stabilizes a bit more :)