Add version-specific BibTeX
As pointed out by @lhoestq in #2411, after the creation of the Zenodo DOI for Datasets, a new BibTeX entry is created with each release.

This PR adds a version-specific BibTeX entry, besides the existing one which is generic for the project.

See version-specific BibTeX entry here: https://zenodo.org/record/4817769/export/hx#.YLSyd6j7RPY