MNT: Remove rdflib-jsonld from requirements
According to https://github.com/RDFLib/rdflib-jsonld:
This rdflib plugin is deprecated for, as of the 2021-09-17 release of rdflib 6.0.1, JSON-LD handing has been integrated. All functionality in this package has been removed, as of release 0.6.2.
Rudimentary testing suggests that nidmresults
works fine without rdflib-jsonld
installed