Small README updates (#29)

* Update README.md

Co-authored-by: Kamil Owczarz <91068263+kowczarz@users.noreply.github.com>

---------

Co-authored-by: Kamil Owczarz <91068263+kowczarz@users.noreply.github.com>

Author: anna1901

README.md

@@ -114,15 +114,15 @@ The `config` object should include:
 ## Example Usage
 Managing a live activity:
 ```javascript
-const state = {
+const state: LiveActivity.LiveActivityState = {
   title: "Title",
   subtitle: "This is a subtitle",
   date: new Date(Date.now() + 60 * 1000 * 5).getTime(),
   imageName: "live_activity_image",
   dynamicIslandImageName: "dynamic_island_image"
 };
 
-const config = {
+const config: LiveActivity.LiveActivityConfig = {
   backgroundColor: "#FFFFFF",
   titleColor: "#000000",
   subtitleColor: "#333333",
@@ -147,9 +147,13 @@ useEffect(() => {
     // Send token to a remote server to update live activity with push notifications
   });
 
-  return () => subscription.remove();
+  return () => subscription?.remove();
 }, []);
 ```
+
+> [!NOTE]
+> Receiving push token may not work on simulators. Make sure to use physical device when testing this functionality.
+
 ## Push notifications
 By default, updating live activity is possible only via API. If you want to have possibility to update live activity using push notifications, you can enable that feature by adding `"enablePushNotifications": true` in the plugin config in your `app.json` or `app.config.ts` file. Then, the notification payload should look like this: