What happens when a wildshaped druid is affected by the Sleep spell?

@JeremyECrawford What happens when a wildshaped druid is affected by the sleep spell. Do they stay in beast form or revert to normal?

— Jonathan Longstaff (@pukunui81) February 18, 2016

Wild Shape ends if you're knocked unconscious, so if the sleep spell knocks you unconscious, Wild Shape ends. #DnD https://t.co/2fj1Uu3B4f

— Jeremy Crawford (@JeremyECrawford) February 22, 2016