Move to Apple Silicon based runner

Remove cmake as we no longer need to build ninja. We can use the
official wheel now since the runner's Python is 3.9 (before: 3.8).

Use the same comment regarding '--wrap-mode' as in the other jobs.

Download and use official ccache binary.

Add myself to the 'only' section in .gitlab-ci.yml so I can have
CI in my fork.

Disable a few deprecation warnings due to the much newer SDK of
the Apple Silicon machine.

gio/gcocoanotificationbackend.m

@@ -106,6 +106,11 @@ activate_detailed_action (const char * action)
     }
 }
 
+G_GNUC_BEGIN_IGNORE_DEPRECATIONS
+/* first deprecated in macOS 11.0 - All NSUserNotifications API should be
+ * replaced with UserNotifications.frameworks API
+ */
+
 @interface GNotificationCenterDelegate : NSObject<NSUserNotificationCenterDelegate> @end
 @implementation GNotificationCenterDelegate
 
@@ -263,6 +268,8 @@ g_cocoa_notification_backend_withdraw_notification (GNotificationBackend *backen
   [str_id release];
 }
 
+G_GNUC_END_IGNORE_DEPRECATIONS
+
 static void
 g_cocoa_notification_backend_init (GCocoaNotificationBackend *backend)
 {

gio/gosxappinfo.m

@@ -656,7 +656,10 @@ g_osx_app_info_get_all_for_scheme (const char *cscheme)
   gint i;
   
   scheme = create_cfstring_from_cstr (cscheme);
+  G_GNUC_BEGIN_IGNORE_DEPRECATIONS
+  /* first deprecated in macOS 10.15 - Use LSCopyApplicationURLsForURL() instead */
   bundle_list = LSCopyAllHandlersForURLScheme (scheme);
+  G_GNUC_END_IGNORE_DEPRECATIONS
   CFRelease (scheme);
 
   if (!bundle_list)
@@ -795,7 +798,10 @@ g_app_info_get_default_for_uri_scheme_impl (const char *uri_scheme)
   NSBundle *bundle;
 
   scheme = create_cfstring_from_cstr (uri_scheme);
+  G_GNUC_BEGIN_IGNORE_DEPRECATIONS
+  /* first deprecated in macOS 10.15 - Use LSCopyDefaultApplicationURLForURL() instead. */
   bundle_id = LSCopyDefaultHandlerForURLScheme (scheme);
+  G_GNUC_END_IGNORE_DEPRECATIONS
   CFRelease (scheme);
 
   if (!bundle_id)