CI Unpin pytest and regenerate lock-files

[lesteve]

This is mostly a behaviour changes from https://docs.pytest.org/en/stable/changelog.html#other-breaking-changes

#9288: warns() now re-emits unmatched warnings when the context closes – previously it would consume all warnings, hiding those that were not matched by the function.

I think this behaviour change makes sense and adapting our tests is easy and not controversial.

and a work-around for a pytest bug: pytest-dev/pytest#11872

It seems like pytest --pyargs sklearn in pytest 8 does not discover tests with Meson editable install for some weird reason, it could be because of collection changes in Pytest 8 maybe https://docs.pytest.org/en/stable/changelog.html#collection-changes? It seems like a meson-python issue actually, I have opened mesonbuild/meson-python#568. I think pytest --pyargs is actually broken in editable installs and is somehow working by chance with pytest<8

[github-actions]

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[lesteve]

So the CI is green but codecov fails to upload see build log. One example where having disallowed "Bypass required checks" is a minor downside. I have retriggered the failing build and it passes.

[glemaitre]

LGTM