Is this true, though? Looking at the ICD-11 draft [0], burnout appears in chapter 24 which lists "factors influencing health status or contact with health services" but no proper disorders. This has already been the case since the release of ICD-10 [1]. So there doesn't appear to be a change.
[0] https://icd.who.int/browse11 [1] https://icd.who.int/browse10/2016/en#/Z73.0