Update objc2 to v0.2.2 (#3702)

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

src/platform_impl/macos/event_loop.rs

@@ -14,7 +14,7 @@ use core_foundation::runloop::{
     kCFRunLoopCommonModes, CFRunLoopAddSource, CFRunLoopGetMain, CFRunLoopSourceContext,
     CFRunLoopSourceCreate, CFRunLoopSourceRef, CFRunLoopSourceSignal, CFRunLoopWakeUp,
 };
-use objc2::rc::{autoreleasepool, Id};
+use objc2::rc::{autoreleasepool, Retained};
 use objc2::runtime::ProtocolObject;
 use objc2::{msg_send_id, ClassType};
 use objc2_app_kit::{NSApplication, NSApplicationActivationPolicy, NSWindow};
@@ -68,12 +68,12 @@ impl PanicInfo {
 
 #[derive(Debug)]
 pub struct ActiveEventLoop {
-    delegate: Id<ApplicationDelegate>,
+    delegate: Retained<ApplicationDelegate>,
     pub(super) mtm: MainThreadMarker,
 }
 
 impl ActiveEventLoop {
-    pub(super) fn new_root(delegate: Id<ApplicationDelegate>) -> RootWindowTarget {
+    pub(super) fn new_root(delegate: Retained<ApplicationDelegate>) -> RootWindowTarget {
         let mtm = MainThreadMarker::from(&*delegate);
         let p = Self { delegate, mtm };
         RootWindowTarget { p, _marker: PhantomData }
@@ -186,12 +186,12 @@ pub struct EventLoop<T: 'static> {
     ///
     /// We intentionally don't store `WinitApplication` since we want to have
     /// the possibility of swapping that out at some point.
-    app: Id<NSApplication>,
+    app: Retained<NSApplication>,
     /// The application delegate that we've registered.
     ///
     /// The delegate is only weakly referenced by NSApplication, so we must
     /// keep it around here as well.
-    delegate: Id<ApplicationDelegate>,
+    delegate: Retained<ApplicationDelegate>,
 
     // Event sender and receiver, used for EventLoopProxy.
     sender: mpsc::Sender<T>,
@@ -225,7 +225,7 @@ impl<T> EventLoop<T> {
         let mtm = MainThreadMarker::new()
             .expect("on macOS, `EventLoop` must be created on the main thread!");
 
-        let app: Id<NSApplication> =
+        let app: Retained<NSApplication> =
             unsafe { msg_send_id![WinitApplication::class(), sharedApplication] };
 
         if !app.is_kind_of::<WinitApplication>() {