build: Fix docker command when selinux is enforced

The DOCKER command was missing :Z for the ~/go directory, failing with:

    $ BUILD_IN_DOCKER=y make all
    ...
    GOOS="linux" GOARCH="arm64"  \
    go build -tags "libvirt_dlopen" -ldflags="-X k8s.io/minikube/pkg/version.version=v1.37.0 ...
    go: could not create module cache: stat /go/pkg/mod: permission denied
    make: *** [Makefile:279: out/minikube-linux-arm64] Error 1
    make: *** [Makefile:276: out/minikube-linux-arm64] Error 2

With this change we can debug build issues on Fedora or other distros
using selinux.

Author: nirs

Makefile

@@ -188,7 +188,7 @@ endef
 
 # $(call DOCKER, image, command)
 define DOCKER
-	docker run --rm -e GOCACHE=/app/.cache -e IN_DOCKER=1 --user $(shell id -u):$(shell id -g) -w /app -v $(PWD):/app:Z -v $(GOPATH):/go --init $(1) /bin/bash -c '$(2)'
+	docker run --rm -e GOCACHE=/app/.cache -e IN_DOCKER=1 --user $(shell id -u):$(shell id -g) -w /app -v $(PWD):/app:Z -v $(GOPATH):/go:Z --init $(1) /bin/bash -c '$(2)'
 endef
 
 ifeq ($(BUILD_IN_DOCKER),y)