[github] Bump actions/download-artifact from 3 to 4 #10

Job	Run time
Build images (linux/amd64, amd64)	4m 30s
Build images (linux/386, i386)	4m 0s
Build images (linux/arm64/v8, arm64v8)	30m 31s
Build images (linux/arm/v7, arm32v7)	25m 41s
Build images (linux/arm/v6, arm32v6)	25m 14s
Build images (linux/riscv64, riscv64)	23m 39s
Build images (linux/ppc64le, ppc64le)	27m 55s
Build images (linux/s390x, s390x)	35m 39s
Publish images	11s
router	0s
	2h 57m 20s

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