clarify "just in time" recommendation in README

The README states: 'Therefore, in addition to the app's privacy policy, you should strongly consider providing a just-in-time notice before the app accesses geolocation data (if the device operating system doesn't do so already).'

It seems that all the methods exposed on this plugin trigger the native permission dialog on iOS. So, there's no way to check that the permission has been enabled or not - which would inform whether or not to show a "just in time" notice.

The only real possibility is to show this "just in time" notice before every use of this plugin – which makes no sense in the case where the user has already granted permission.

Does it make sense to add some functionality that simply checks if the permission has been granted? This method would never trigger the native dialog.