Migrate deprecated Cocoa NSUserNotification* API to UserNotifications.framework
As Apple's instruction here, NSUserNotification has been first deprecated on macOS 11 and may soon unavailable for future macOS releases. The suggested UserNotifications.framework is a newer interface for creating notifications and it is providing Embedded support (typically iOS), currently gio/gcocoanotificationbackend.m
is still using those deprecated APIs which generating compiler warnings.