make certificates non-executable

roles/kubernetes/master/tasks/kubeadm-setup.yml

@@ -128,7 +128,7 @@
     content: "{{ item.content | b64decode }}"
     owner: root
     group: root
-    mode: 0700
+    mode: 0600
   no_log: true
   register: copy_kubeadm_certs
   with_items: "{{ kubeadm_certs.results }}"