Cannot find type 'TimelineEntry' in scope while archiving

Question

I added IOS 14 Widget into my application. It works fine when test on simulator or real device. But when i try to make archive for app store, it throws error that "Cannot find type 'TimelineEntry' in scope". Here is my code for timeline entry.

import Foundation
import WidgetKit

struct WidgetContent: TimelineEntry {
    var date: Date = Date()
    var lastVisibleIndexForDigitPicker: UInt64 = 00
    var isBulbOn: Bool = false
}