This app contains an app extension with an illegal bundle identifier. App extension bundle identifiers must have a prefix consisting of their containing application’s bundle identifier followed by a ‘.’.
原因是demo的Bundle id 与 我们新建的target的Bundle id 不能一致，他们是相互独立的。
原文地址：https://blog.csdn.net/ycf03211230/article/details/54907173
