feat: add macos CI (#1704)

PR adding macOS configuration to Example app and adding CI job for building the app on macOS.

Example/macos/Example-iOS/AppDelegate.m

@@ -0,0 +1,35 @@
+#import "AppDelegate.h"
+
+#import <React/RCTBridge.h>
+#import <React/RCTBundleURLProvider.h>
+#import <React/RCTRootView.h>
+
+@implementation AppDelegate
+
+- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
+{
+  RCTBridge *bridge = [[RCTBridge alloc] initWithDelegate:self launchOptions:launchOptions];
+  RCTRootView *rootView = [[RCTRootView alloc] initWithBridge:bridge
+                                                   moduleName:@"Example"
+                                            initialProperties:nil];
+
+  rootView.backgroundColor = [[UIColor alloc] initWithRed:1.0f green:1.0f blue:1.0f alpha:1];
+
+  self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
+  UIViewController *rootViewController = [UIViewController new];
+  rootViewController.view = rootView;
+  self.window.rootViewController = rootViewController;
+  [self.window makeKeyAndVisible];
+  return YES;
+}
+
+- (NSURL *)sourceURLForBridge:(RCTBridge *)bridge
+{
+#if DEBUG
+  return [[RCTBundleURLProvider sharedSettings] jsBundleURLForBundleRoot:@"index" fallbackResource:nil];
+#else
+  return [[NSBundle mainBundle] URLForResource:@"main" withExtension:@"jsbundle"];
+#endif
+}
+
+@end