Add link to RopenSci website package documentation

[theamarks]

The GitHub repo "About" url is the software archive record associated with the DOI. This DOI url is also listed in the README. I was looking for a human readable rendered vignettes and documentation and settled on navigating through CRAN (first search result).

Not the end of the world, but would help a future user who is too lazy to keep scrolling their search results, although I don't even see https://dataoneorg.r-universe.dev/dataone on the first page of results.

[mbjones]

I changed the github URL to https://dataoneorg.r-universe.dev/dataone. The DOI still resolves to SWH, but that is appropriate for the archival version of the package. It would be good to add the docs URL https://dataoneorg.r-universe.dev/dataone to the README.md in the next release too.