Update docker-compose.yml

Add note for an option that apparently does nothing the way it is described.

For setting up LDAP only, one must disable Password login option in the admin panel

docker-compose.yml

@@ -473,6 +473,7 @@ services:
       # Note: Do not add single quotes '' to variables. Having spaces still works without quotes where required.
       #
       # The default authentication method used if a user does not exist to create and authenticate. Can be set as ldap.
+      # (this is set properly in the Admin Panel, changing this item does not remove Password login option)
       #- DEFAULT_AUTHENTICATION_METHOD=ldap
       #
       # Enable or not the connection by the LDAP