protobuf: add vtproto as a supplemental marshaler #4978

Job	Run time
govulncheck	57s
prepare	3s
binaries (darwin/amd64)	1m 0s
binaries (darwin/arm64)	1m 3s
binaries (linux/amd64)	1m 55s
binaries (linux/arm/v7)	1m 53s
binaries (linux/arm64)	1m 58s
binaries (linux/s390x)	1m 56s
binaries (linux/ppc64le)	1m 55s
binaries (linux/riscv64)	1m 58s
binaries (windows/amd64)	1m 49s
binaries (windows/arm64)	1m 50s
test / prepare	1m 51s
test / run (containerd, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integration)	7m 54s
test / run (containerd-rootless, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integr...	9m 15s
test / run (containerd-1.6, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integration)	7m 30s
test / run (containerd-snapshotter-stargz, ./client ./cmd/buildctl ./worker/containerd ./solver ./fronte...	8m 45s
test / run (oci, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integration)	5m 5s
test / run (oci-rootless, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integration)	5m 6s
test / run (oci-rootless-slirp4netns-detachnetns, ./client ./cmd/buildctl ./worker/containerd ./solver ....	5m 9s
test / run (oci-snapshotter-stargz, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, int...	8m 47s
test / run (./..., 1, integration gateway)	4m 17s
test / run (./client, containerd, nydus, integration)	7m 43s
test / run (./client, oci, nydus, integration)	6m 59s
test / run (./..., nydus, 1, integration)	4m 17s
image	8m 42s
image (rootless)	8m 49s
release	9s
scout	0s
	1h 58m 35s

Provide feedback