Improving yamllint configuration (#11389)

Signed-off-by: Bas Meijer <bas.meijer@enexis.nl>

roles/kubernetes/preinstall/tasks/0080-system-configurations.yml

@@ -29,7 +29,7 @@
     state: present
     create: yes
     backup: yes
-    mode: 0644
+    mode: "0644"
   when:
     - disable_ipv6_dns
     - not ansible_os_family in ["Flatcar", "Flatcar Container Linux by Kinvolk"]
@@ -67,7 +67,7 @@
   file:
     name: "{{ sysctl_file_path | dirname }}"
     state: directory
-    mode: 0755
+    mode: "0755"
 
 - name: Enable ip forwarding
   ansible.posix.sysctl: