Backport PR #4018 on branch 1.12.x (ci: bump codecov/codecov-action from 5 to 6) #1598

Job	Run time
build	26s
get-environments	9s
test (hatch-test.low-vers, coverage, 3.12)	11m 11s
test (hatch-test.pre, coverage, 3.14)	7m 11s
test (hatch-test.few-extras, 3.14)	5m 50s
test (hatch-test.stable, 3.14)	6m 46s
check	2s
	31m 35s

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