Just a heads up that I was fighting against this also and have a bit different error. After manually adding some info to the plist to fix other errors, I am left still getting this error even though the correct Bundle Icon Name info is in the plist.
Missing Info.plist value - A value for the Info.plist key CFBundleIconName is missing in the bundle.
Thread with more info on my findings.
https://forums.unrealengine.com/development-discussion/ios-development/1344418-error-publishing-to-app-store-with-ios11-and-xcode-9-beta-6-for-testflight