Version 7.1.0

### 7.1.0
-   Breaking Changes
    - Remote Config: Changed `FirebaseRemoteConfig` to be an instanced class,
      with new APIs to better manage fetching config data. The old static
      methods are now deprecated, and can be accessed in the new class
      `FirebaseRemoteConfigDeprecated`.
    - Remote Config: `ConfigSettings.IsDeveloperMode` is now obsolete and does
      nothing. `ConfigSettings.MinimumFetchInternalInMilliseconds` should be
      adjusted instead.
-   Changes
    - General: Add GoogleServices-Info.plist to `Unity-iPhone` target in
      Unity 2019.3+.
    - Firestore: Fixed partial updates in `UpdateAsync()` with
      `FieldValue.Delete`
      ([#882](https://github.com/firebase/quickstart-unity/issues/882)).
    - Firestore: Fixed `DocumentSnapshot.ToDictionary()` on non-existent
      documents when running on Android
      ([#887](https://github.com/firebase/quickstart-unity/issues/887)).
    - Firestore: Fixed crash setting FirebaseFirestore.LogLevel on Android
      before any instances have been created
      ([#888](https://github.com/firebase/quickstart-unity/issues/888)).
    - Auth: Fixed a flaky crash when accessing the result from the task returned
      by `FetchProvidersForEmailAsync`.
    - Auth: You can now specify a language for emails and text messages sent
      from your apps using UseAppLanguage() or setting the
      FirebaseAuth.LanguageCode property.
    - Messaging (Android): Using `enqueueWork` instead of `startService`.
      Fixes bug where we lost messages with data payloads received when app
      is in background.
      ([#877](https://github.com/firebase/quickstart-unity/issues/877)
    - Remote Config: Fixed numeric value conversion `ConfigValue.DoubleValue`
      and `ConfigValue.LongValue` to be locale independent.
    - Installations: Fixed pod version to 7.5.0.