Switch from golang/mock to uber-go/mock

See https://github.com/golang/mock#gomock: golang/mock is no longer
maintained, and should be replaced by go.uber.org/mock.

This allows golang/mock to be dropped from the status and vendored
fields in unwanted-dependencies.json.

Signed-off-by: Stephen Kitt <skitt@redhat.com>

hack/update-mocks.sh

@@ -27,7 +27,7 @@ source "${KUBE_ROOT}/hack/lib/init.sh"
 kube::golang::setup_env
 
 echo 'installing mockgen'
-go -C "${KUBE_ROOT}/hack/tools" install github.com/golang/mock/mockgen
+go -C "${KUBE_ROOT}/hack/tools" install go.uber.org/mock/mockgen
 
 function git_grep() {
   git grep --untracked --exclude-standard \