XSD Schema not allow %env()% syntax

[gimler]

I try to use

<monolog:handler
  name="file"
  type="error_log"
  level="%env(APP_LOG_LEVEL)%"
/>

error

In FileLoader.php line 174:
                                                                                                                             
[ERROR 1840] Element '{http://symfony.com/schema/dic/monolog}handler', attribute 'level': [facet 'enumeration'] The value '%env(APP_LOG_LEVEL)%' is not an element of the set {'debug', 'info', 'notice', 'warning', 'error', 'critical', 'alert', 'emergency', 'DEBUG', 'INFO', 'NOTICE', 'WARNING', 'ERROR', 'CRITICAL', 'ALERT', 'EMERGENCY', '100', '200', '250', '300', '400', '500', '550', '600'}.                                                                                                                  

see https://github.com/symfony/monolog-bundle/blob/master/Resources/config/schema/monolog-1.0.xsd#L97