use new ansible syntax
    
    addressing:
     [DEPRECATION WARNING]: Legacy variable substitution, such as using ${foo} or
    $foo instead of {{ foo }} is currently valid but will be phased out and has
    been out of favor since version 1.2. This is the last of legacy features on our
    deprecation list. You may continue to use this if you have specific needs for
    now. This feature will be removed in version 1.6. Deprecation warnings can be
    disabled by setting deprecation_warnings=False in ansible.cfg.