Refreeze dask-gateway-server/Dockerfile.requirements.txt #795

Job	Run time
Test k8s backend & chart (v1.24, default)	5m 58s
Test hadoop backend	2m 10s
main-tests (3.9, 1.20)	2m 28s
Test k8s backend & chart (v1.25, separate-namespace)	6m 1s
Test pbs backend	1m 43s
main-tests (3.10, 1.21)	2m 31s
Test k8s backend & chart (v1.26, default, 2022.4.0)	6m 36s
Test slurm backend	1m 33s
main-tests (3.11, 1.21)	2m 43s
Test k8s backend & chart (v1.27, default)	5m 57s
main-tests (3.12, 1.21)	2m 55s
Test k8s backend & chart (v1.28, default)	6m 6s
	46m 41s

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