add sudoers check with visudo as proposed here: https://blog.afoolishmanifesto.com/posts/checking-sudoers-with-visudo-in-saltstack/

sudoers/init.sls

@@ -11,6 +11,7 @@ sudo:
     - mode: 440
     - template: jinja
     - source: salt://sudoers/files/sudoers
+    - check_cmd: /usr/sbin/visudo -c -f
     - context:
         included: False
     - require: