Update cache action to v4 #4089

Job	Run time
collateral (diffcov)	6m 11s
collateral (docs)	55s
test_cygwin (39, windows-latest)	14m 9s
test (3.8, ubuntu-latest)	4m 16s
test (3.8, macos-latest)	7m 49s
test (3.8, windows-latest)	8m 13s
test (3.11, ubuntu-latest)	4m 3s
test (3.11, macos-latest)	6m 39s
test (3.11, windows-latest)	10m 33s
test (3.12, ubuntu-latest)	6m 0s
test (3.12, macos-latest)	12m 11s
test (3.12, windows-latest)	12m 9s
test (3.9, ubuntu-latest)	4m 5s
test (3.10, ubuntu-latest)	3m 46s
test (pypy3.10, ubuntu-latest, stdlib)	6m 31s
test (ubuntu-latest, 3.10, stdlib)	3m 46s
integration-test	0s
check	2s
release	0s
	1h 51m 18s

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