You can still submit your app to support AppTrackingTransparency framework with Xcode 11.7 by using below conditional checks which compile framework when its available for specific Xcode version :-
Objective C
#if _hasinclude(<AppTrackingTransparency/AppTrackingTransparency.h>)
#import <AppTrackingTransparency/AppTrackingTransparency.h>
#endif
Swift
#if canImport(AppTrackingTransparency)
import AppTrackingTransparency
#endif