Code to check if there is a new version on AppStore.

This code is a version based on @anupgupta-arg's code.

You can force the update by calling

CheckUpdate.shared.showUpdate(withConfirmation: false)

Or the user can choose if he wants to update now or later by calling

CheckUpdate.shared.showUpdate(withConfirmation: true)

Inside the code has a link from iTunes. There, you should pay attention and put the country where the application is available. Like this: http://itunes.apple.com/<country>/lookup?bundleId=\(identifier)

For example:

• let url = URL(string: "http://itunes.apple.com/br/lookup?bundleId=\(identifier)") if the application is available in Brazil

• By calling CheckUpdate.shared.showUpdate(withConfirmation: true)

• By calling CheckUpdate.shared.showUpdate(withConfirmation: false)