[x] Switch from setup.cfg/setup.py to pyproject.toml
[x] Use requirements.in to build the constraints file. This is messy, and would probably lead us to a wrapper like Poetry, in order to have a proper lock file. Because pip does not support hashes in editable mode, and pip-compile does not pick extra dependencies from pyproject.toml, they therefore have to be duplicated in a requirements.in file.
[x] Update release docs. One-click release! But I left the 3 steps that consist in checking that everything is ready and that everything was published correctly
Repo modernization!
requirements.in
to build the constraints file. This is messy, and would probably lead us to a wrapper like Poetry, in order to have a proper lock file. Because pip does not support hashes in editable mode, and pip-compile does not pick extra dependencies from pyproject.toml, they therefore have to be duplicated in a requirements.in file.