tests

Exclude coverage for older Python version checks #4694

Job	Run time
test_cygwin (39, windows-latest)	13m 54s
collateral (diffcov)	5m 26s
test (3.8, ubuntu-latest)	3m 47s
collateral (docs)	1m 55s
test (3.8, windows-latest)	10m 32s
collateral (check-extern)	13s
test (3.12, ubuntu-latest)	5m 26s
test (3.12, macos-latest)	4m 10s
test (3.12, windows-latest)	11m 45s
test (3.9, ubuntu-latest)	4m 34s
test (3.10, ubuntu-latest)	3m 42s
test (3.11, ubuntu-latest)	4m 9s
test (pypy3.10, ubuntu-latest, stdlib)	6m 39s
test (ubuntu-latest, 3.10, stdlib)	3m 54s
test (3.8, macos-13)	6m 22s
integration-test	0s
check	2s
release	0s
	1h 26m 30s

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