Listing extra requirements in setup.cfg

[hgrecco]

I have noticed that our extra requirements is inconsistent. It currently looks like this.

numpy = numpy >= 1.19.5
uncertainties = uncertainties >= 3.1.6
test =
    pytest
    pytest-mpl
    pytest-cov
    pytest-subtests

Pint interacts with more projects (if available), not just numpy and uncertainties. My suggestion would be to include as independent lines everything that is optional: babel, pandas (which should install pint-pandas), xarray, dask.

[hgrecco]

Which versions should we specify for each package. The minimal would be:

[options.extras_require]
numpy = numpy >= 1.19.5
uncertainties = uncertainties >= 3.1.6
babel = babel >= 2.8
pandas = pint-pandas
xarray = xarray
dask = dask
test =
    pytest
    pytest-mpl
    pytest-cov
    pytest-subtests

but maybe we should be more strict?

[andrewgsavage]

pint-pandas >= 0.3

[jules-ch]

babel <= 2.8 for now