Add gpg-agent package, required by coverage job #97

Job	Run time
build (linux/amd64, ubuntu-24.04, bookworm, gcc, 12)	1m 26s
build (linux/amd64, ubuntu-24.04, bookworm, gcc, 13)	1m 28s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 16)	1m 31s
build (linux/amd64, ubuntu-24.04, bookworm, gcc, 14)	1m 41s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 19)	1m 33s
build (linux/arm64, ubuntu-24.04-arm, bookworm, gcc, 12)	2m 18s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 18)	1m 31s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 17)	2m 22s
build (linux/arm64, ubuntu-24.04-arm, bookworm, gcc, 14)	2m 13s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 16)	2m 23s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 19)	1m 58s
build (linux/arm64, ubuntu-24.04-arm, bookworm, gcc, 13)	2m 20s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 17)	1m 34s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 20)	1m 27s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 20)	2m 15s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 18)	2m 2s
merge	0s
	30m 2s

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