Compatibility with python 3.11 is blocked by GPy 1.10.0

[muxator]

Black-it cannot be made compatible with python 3.11 because GPy does not build with python 3.11.

This is the issue, with no solution for now: https://github.com/SheffieldML/GPy/issues/998

[marcofavorito]

I suggest using the extra-dependencies mechanism of setuptools to overcome limitations of this kind.

We could have the following extras:

• [all]: install all dependencies from all extras
• [X-sampler]: install all dependencies to make X sampler to work
• [X-loss]: install all dependencies to make X loss function to work.

I'd avoid the last item for the moment; but for "forward-compatibility" of the nomenclature, I'd leave the -sampler suffix.

E.g. for GPy, we could have the extra called gp-sampler, that installs GPy on-demand, and not installed if not needed by the user.

What do you think? I'll try to draft a PR on this idea.