Bump actions/checkout from 5 to 6 #3467

Job	Run time
test-unit (3.12)	1m 20s
test-misc (3.10)	16s
test-unit (3.10)	1m 37s
test-integration (3.10, not postgres and not slurm)	4m 1s
test-integration (3.12, not postgres and not slurm)	4m 18s
test-unit (3.11)	1m 24s
test-integration (3.9, not postgres and not slurm)	4m 8s
test-regression (3.9)	1m 30s
test-regression (3.10)	1m 28s
test-unit (3.9)	1m 27s
test-integration (3.9, postgres and not slurm)	1m 57s
test-regression (3.12)	1m 18s
test-regression (3.11)	1m 20s
test-docs (3.9)	3m 15s
test-integration (3.11, not postgres and not slurm)	3m 41s
test-slurm (3.9)	4m 38s
coverage	0s
	37m 38s

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