Update objc2 to v0.2.2 (#3702)

- Use new `bitflags!` support.
- Use `objc2-ui-kit`.
- Change usage of `Id` to `Retained`.

src/platform/ios.rs

@@ -357,7 +357,7 @@ impl MonitorHandleExtIOS for MonitorHandle {
     fn ui_screen(&self) -> *mut c_void {
         // SAFETY: The marker is only used to get the pointer of the screen
         let mtm = unsafe { objc2_foundation::MainThreadMarker::new_unchecked() };
-        objc2::rc::Id::as_ptr(self.inner.ui_screen(mtm)) as *mut c_void
+        objc2::rc::Retained::as_ptr(self.inner.ui_screen(mtm)) as *mut c_void
     }
 
     #[inline]