Treat `pytest` warnings as errors #453

Job	Run time
Build distribution packages	18s
Test documentation website generation	0s
Test with nox (ubuntu-20.04, 3.11, ci_checks_max)	6m 24s
Cross-arch tests with nox (arm64, ubuntu-20.04, 3.11, pytest_min)	7m 34s
Test with nox (ubuntu-20.04, 3.11, pytest_min)	26s
Cross-arch tests with nox (arm64, ubuntu-20.04, 3.11, pytest_max)	7m 45s
Test package installation in different architectures	1m 32s
Test with nox	1s
Cross-arch tests with nox	1s
Publish documentation website to GitHub pages	0s
Create GitHub release	0s
Publish packages to PyPI	0s
	24m 1s

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