Most of these are minor and would have been selected by the semant-
ic version string during `poetry install`, but I want to make sure
that they are as current as possible before I leave the project.
In the case of Pandas 1.4.0 the minimum Python version is actually
only 3.8, so let's set that as the minimum.
Remove pylode because Marie says she was only using it for the HTML
docs, but I'm doing that differently now. This means we can have a
direct dependency on rdflib now.
Also, move isort and black to dev dependencies because nobody will
need them except me. :)
Currently covers the dependencies used in Marie's Jupyter notebook
and some extra dev tooling. Note that I had an issue using poetry
to install pylode, so I added it to pyproject.toml manually.