Update react-native PushNotificationIOS Typings

React-Native typings are currently missing two crucial definitions when implementing iOS notifications: finish function and FetchResult strings. If a finish function is not called, the background remote notifications could be throttled.

Sources:
https://facebook.github.io/react-native/docs/pushnotificationios.html#finish
https://github.com/facebook/react-native/blob/master/Libraries/PushNotificationIOS/PushNotificationIOS.js#L133
https://github.com/facebook/react-native/blob/master/Libraries/PushNotificationIOS/PushNotificationIOS.js#L454

types/react-native/index.d.ts

@@ -7160,6 +7160,12 @@ export interface PushNotification {
      * Gets the data object on the notif
      */
     getData(): Object;
+                                                                                     
+    /**
+     * iOS Only
+     * Signifies remote notification handling is complete
+     */
+    finish(result: string): void;
 }
 
 type PresentLocalNotificationDetails = {
@@ -7182,6 +7188,12 @@ type ScheduleLocalNotificationDetails = {
 };
 
 export type PushNotificationEventName = "notification" | "localNotification" | "register" | "registrationError";
+                                                                                     
+type FetchResult = {
+    NewData: "UIBackgroundFetchResultNewData",
+    NoData: "UIBackgroundFetchResultNoData",
+    ResultFailed: "UIBackgroundFetchResultFailed"
+};
 
 /**
  * Handle push notifications for your app, including permission handling and icon badge number.
@@ -7296,6 +7308,12 @@ export interface PushNotificationIOSStatic {
      * object if the app was launched by a push notification, or `null` otherwise.
      */
     getInitialNotification(): Promise<PushNotification>;
+                                                                                     
+    /**
+     * iOS fetch results that best describe the result of a finished remote notification handler.
+     * For a list of possible values, see `PushNotificationIOS.FetchResult`.
+     */
+    FetchResult: FetchResult;
 }
 
 export interface SettingsStatic {