MAINT: fix the way to point to the license file

[glemaitre]

When using pixi-build to create the conda package, the current way to specify the license does not work because it makes the parsing failed with an unrecognized type of license.

Looking at the documentation, i.e. https://hatch.pypa.io/1.13/config/metadata/#spdx-expression, license should be a string mentioning the type of license. Here, we want to point to a license file and we should be using license-files instead.

[glemaitre]

It looks like the error is unrelated and is due to a deprecation warning in scikit-learn.

[adrinjalali]

Yeah the error is from PassiveAggressiveRegressor, I need to fix that in the CI.

[adrinjalali]

Why are you building in conda? The conda-forge package is available 😁

[glemaitre]

I revamped my Python stack workspace that uses pixi: https://github.com/glemaitre/python-stack/

When installing from source, pixi is building a conda package as an intermediate stage. Then, if there is any change in the source, it will rebuild it. It is pretty experimental (it is rebuild a bit too much at the moment) but it is quite nice.