iOS 12.1.1 Coming Today With Expanded eSIM Support,
FaceTime Live Photos, Face ID Bug Fix, and More
https://www.macrumors.com/2018/12/05/ios-12-1-1-coming-today/
重點：
One tap to flip between the rear and front-facing camera during a
FaceTime call
這功能超重要的，之前藏起來實在是有夠白痴的