python: test generated wheels in different environments

[reyammer]

python wheels are generated in https://github.com/google/magika/blob/main/.github/workflows/maturin.yml for the three OSes (linux, mac, windows) and we do run some tests there. However, there are currently no tests of these wheels in different settings, such as different versions of python and different versions of these operating systems (e.g., ubuntu 20.04).

The challenge is that we would need to find a way to pick up the artifacts built in the maturin workflow and then use them in different gh runners with different OSes and python versions.

It seems it would be possible to download an artifact that has been generated in another gh action (see https://github.com/actions/download-artifact), but this requires some non-trivial work.