`owlrl --help` in 6.x fails, trying to import old constants (e.g. RDFXML)

[bollwyvl]

Discovered on conda-forge where we execute owlrl --help as part of the tests, It looks like the scripts were not updated for 6.x, after the removal of all of the various format strings were removed:

Traceback (most recent call last):
  File "/home/conda/feedstock_root/build_artifacts/owlrl_1633874681694/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_/bin/owlrl", line 6, in <module>
    from owlrl._cli import main
  File "/home/conda/feedstock_root/build_artifacts/owlrl_1633874681694/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_/lib/python3.9/site-packages/owlrl/_cli.py", line 5, in <module>
    from owlrl import convert_graph, RDFXML, TURTLE, JSON, AUTO, RDFA
ImportError: cannot import name 'RDFXML' from 'owlrl' (/home/conda/feedstock_root/build_artifacts/owlrl_1633874681694/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_/lib/python3.9/site-packages/owlrl/__init__.py)

As I know folk actually do use the command line tool, I'm probably just not going to ship that release on conda-forge.

Related:

• We patch the scripts in setup.py to be cross-platform entry_points
  • the 6.x line may be an appropriate time to change this
    • and potentially add this to the test suite
• Another nice thing would be a --version CLI flag