Deprecated API: Fix crash with UIFontDescriptor.FeatureKey keys
On Xcode 13 + iOS <=14, there is a crash when using UIFontDescriptor.FeatureKey deprecated keys.
In UIFontDescriptor.FeatureKey, .featureIdentifier and .typeIdentifier have been replaced with .type and .selector respectively.
See https://developer.apple.com/documentation/uikit/uifontdescriptor/featurekey