Add gpg-agent package, required by coverage job #96

Job	Run time
build (linux/amd64, ubuntu-24.04, bookworm, clang, 16)	1m 43s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 18)	1m 36s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 20)	1m 34s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 17)	1m 29s
build (linux/amd64, ubuntu-24.04, bookworm, gcc, 13)	1m 34s
build (linux/amd64, ubuntu-24.04, bookworm, gcc, 14)	1m 38s
build (linux/amd64, ubuntu-24.04, bookworm, gcc, 12)	1m 28s
build (linux/arm64, ubuntu-24.04-arm, bookworm, gcc, 13)	2m 26s
build (linux/arm64, ubuntu-24.04-arm, bookworm, gcc, 14)	2m 13s
build (linux/arm64, ubuntu-24.04-arm, bookworm, gcc, 12)	1m 56s
build (linux/amd64, ubuntu-24.04, bookworm, clang, 19)	1m 28s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 17)	1m 50s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 18)	2m 19s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 20)	1m 53s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 19)	2m 3s
build (linux/arm64, ubuntu-24.04-arm, bookworm, clang, 16)	2m 15s
merge	0s
	29m 25s

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