Skosprovider-rdf

------------------

- Don't export local id as dcterms.identifier when it's equal to the URI (117)
- Add support for Python 3.10 and Python 3.11 (120)

------------------

- Better RDF rendering for concepts part of a collection (104)

------------------

- Drop python 3.6 and 3.7 support, add support for 3.8, 3.9 and 3.10
- Update RDFLib to 6.2.0

------------------

- Drop python 2 support
- Upgrade all requirements (90)

------------------

- Cleaner handling of `infer_concept_relations`. When exporting through
skosprovider_rdf this attribute will determine if broader/narrower relations
between concepts are generated when there's a collection between them, as is
the case when a concept has a guide term divding the underlying concepts.
When reading from an RDF file, the `infer_concept_relations` attribute will
be set to True if at least one concept in a collection under a concept has a
broader relation with said concept. (73)
- Prevent the _add_labels method from generating an error. (80)

------------------

- Update to RDFlib 0.5.0 (74)