Run unittest for every supported python version.

[folmos-at-orange]

Description

Currently, we only run the unittests for python 3.10. We should do it for every python version supported (3.8 -> 3.12).

Questions/Ideas

• Add miniconda to the dev docker with 5 envs (one for each python) and mpich installed.
• Remove from the dev docker mpich system-wide installation
• Make the python version a matrix in the CI

[popescu-v]

IMHO, we should also keep the out-of-Conda-environment tests (and the system-wide MPICH), in order to keep testing the KhiopsLocalRunner behaviour on genuine system-wide installations (especially wrt. MPI detection integration tests).

[folmos-at-orange]

IMHO, we should also keep the out-of-Conda-environment tests (and the system-wide MPICH), in order to keep testing the KhiopsLocalRunner behaviour on genuine system-wide installations (especially wrt. MPI detection integration tests).

Right, then we should have the following variants of khiopspydev:

• For systemwide the following OSs: rocky8, rocky9, ubuntu22.04, ubuntu20.04
• For conda: conda-py38, conda-py39, conda-py310, conda-py311, conda-py312

Note that the latest git ref for khiops is 10.2.x-hotfix.