Update readme

readme-vars.yml

@@ -35,6 +35,8 @@ opt_param_usage_include_env: true
 opt_param_env_vars:
   - { env_var: "fleet_admin_secret", env_value: "randomstring", desc: "A string used as part of the password key derivation process." }
 
+readonly_supported: true
+
 app_setup_block_enabled: true
 app_setup_block: |
   Navigate to `http://your_ip_here:8080` to display the home page. If `DATABASE` is selected as the preferred authentication process, ensure that you set up an