Add ValueNotifier & InheritedNotifier as state management option (flu…

…tter#10307)

A solution using the built-in functionality in the Flutter SDK such as
InheritedNotifier and ValueNotifier.

The other documentation doesn't reference the use of these two together
which results in a simple approach to immutable state management

## Presubmit checklist

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Co-authored-by: Brett Morgan <[email protected]>

src/data-and-backend/state-mgmt/options.md

@@ -59,6 +59,15 @@ The low-level approach to use for widget-specific, ephemeral state.
 [Adding interactivity to your Flutter app]: /ui/interactivity
 [Basic state management in Google Flutter]: {{site.medium}}/@agungsurya/basic-state-management-in-google-flutter-6ee73608f96d
 
+## ValueNotifier & InheritedNotifier
+
+An approach using only Flutter provided tooling to update state and notify the UI of changes.
+
+
+* [State Management using ValueNotifier and InheritedNotifier][], by Tadas Petra
+
+[State Management using ValueNotifier and InheritedNotifier]: https://www.hungrimind.com/articles/flutter-state-management
+
 ## InheritedWidget & InheritedModel
 
 The low-level approach used to communicate between ancestors and children