Appstore error: "your app is using the advertising identifier (IDFA)"

This method worked for me, but I also removed one additional bit of code not mentioned in the post:

in Engine/Source/Runtime/Core/Core.Build.cs

In the below block I removed the reference to “AdSupport”:

if (Target.Platform == UnrealTargetPlatform.IOS)
			{
				PublicFrameworks.AddRange(new string[] { "CoreMotion", "AdSupport" });
                AddEngineThirdPartyPrivateStaticDependencies(Target,
                    "PLCrashReporter"
                    );
			}