Add vendor dependencies as part git repo

vendor/sigs.k8s.io/json/Makefile

@@ -0,0 +1,35 @@
+.PHONY: default build test benchmark fmt vet
+
+default: build
+
+build:
+	go build ./...
+
+test:
+	go test sigs.k8s.io/json/...
+
+benchmark:
+	go test sigs.k8s.io/json -bench . -benchmem
+
+fmt:
+	go mod tidy
+	gofmt -s -w *.go
+
+vet:
+	go vet sigs.k8s.io/json
+
+	@echo "checking for external dependencies"
+	@deps=$$(go mod graph); \
+	if [ -n "$${deps}" ]; then \
+		echo "only stdlib dependencies allowed, found:"; \
+		echo "$${deps}"; \
+		exit 1; \
+	fi
+
+	@echo "checking for unsafe use"
+	@unsafe=$$(go list -f '{{.ImportPath}} depends on {{.Imports}}' sigs.k8s.io/json/... | grep unsafe || true); \
+	if [ -n "$${unsafe}" ]; then \
+		echo "no dependencies on unsafe allowed, found:"; \
+		echo "$${unsafe}"; \
+		exit 1; \
+	fi