CI: fix the CI failures on packaging > 22

[frostming]

Because there are test cases against indexes for other languages and their version don't follow the python standards, we have to set version cap of packaging to <22.0 for testing.

Also, switch to nox in CI workflows.

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Fixes #114

[frostming]

Python 2.7 is failing due to incompatible nox. Since we are going to drop 2.7(#116) I prefer to remove it from the matrix.

[kitterma]

What's the solution for those that don't have the option to stay with the old version?

[frostming]

What's the solution for those that don't have the option to stay with the old version?

That is the test dependency and resolvelib itself doesn't have any dependency

[kitterma]

Right, but the environment I'm looking at (Debian Testing) has the newer version, so running the tests with the older version isn't an option. Maybe put the relevant tests inside try/except and then pass on that error from packaging so testing with the newer version at least doesn't cause inappropriate test failures? Scott K

[uranusjr]

The Swift tests actually implement a hand-rolled extremely simplified parser, perhaps we could do the same? https://github.com/sarugaku/resolvelib/blob/master/tests/functional/swift-package-manager/test_resolvers_swift.py