https://github.com/symfony/symfony-docs/blob/master/reference/configuration/twig.rst#cache shows that we need to specify null if we want to disable cache. However, https://github.com/twigphp/Twig/blob/60a8f465d6f259c92a8fe0fb61cf8f767bd8d025/lib/Twig/Environment.php#L247 states that we need false instead.

Also, the type is either string|bool|Twig_CacheInterface. I'm not sure if the docs support multi-types though.