Run make verify with python3 to fix publishing bot issue

verify-publishing-bot is experiencing errors importing pyyaml since
python3 was added to kubekins-e2e image. This changes make verify to run
verify-publishing-bot with python3.

Signed-off-by: hasheddan <georgedanielmangum@gmail.com>

hack/make-rules/verify.sh

@@ -220,7 +220,7 @@ fi
 
 ret=0
 run-checks "${KUBE_ROOT}/hack/verify-*.sh" bash
-run-checks "${KUBE_ROOT}/hack/verify-*.py" python
+run-checks "${KUBE_ROOT}/hack/verify-*.py" python3
 missing-target-checks
 
 if [[ ${ret} -eq 1 ]]; then