update gazel to v8

hack/update-bazel.sh

@@ -20,5 +20,5 @@ set -o pipefail
 export KUBE_ROOT=$(dirname "${BASH_SOURCE}")/..
 source "${KUBE_ROOT}/hack/lib/init.sh"
 
-go get -u gopkg.in/mikedanese/gazel.v4/gazel
+go get -u gopkg.in/mikedanese/gazel.v8/gazel
 "${GOPATH}/bin/gazel" -root="$(kube::realpath ${KUBE_ROOT})"

hack/verify-bazel.sh

@@ -20,7 +20,7 @@ set -o pipefail
 export KUBE_ROOT=$(dirname "${BASH_SOURCE}")/..
 source "${KUBE_ROOT}/hack/lib/init.sh"
 
-go get -u gopkg.in/mikedanese/gazel.v4/gazel
+go get -u gopkg.in/mikedanese/gazel.v8/gazel
 if [[ $("${GOPATH}/bin/gazel" -dry-run -print-diff -root="$(kube::realpath ${KUBE_ROOT})" 2>&1 | tee /dev/stderr | wc -l | tr -d '[:space:]') != 0 ]]; then
   echo
   echo "BUILD files are not up to date"