fix checkmode for letsencrypt

tasks/letsencrypt_cert.yml

@@ -43,6 +43,7 @@
     authorized_key:
       user: letsencrypt
       key: "{{ letsencrypt_renewkey.public_key }}"
+    when: not ansible_check_mode
   - name: add server token to record whitelist on backend server
     when:
     - challenge is changed