Update random number example from StateNotifier to NotifierProvider

examples/random_number/lib/main.dart

@@ -1,4 +1,4 @@
-import 'dart:math';
+1import 'dart:math';
 
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
@@ -9,18 +9,17 @@ void main() {
 
 // State notifier for generating a random number exposed by a state notifier
 // provider
-class RandomNumberGenerator extends StateNotifier<int> {
-  RandomNumberGenerator() : super(Random().nextInt(9999));
-
+class RandomNumberGenerator extends Notifier<int>  {
+  @override
+  int build() => Random().nextInt(9999);
+
   void generate() {
     state = Random().nextInt(9999);
   }
 }
 
 // State notifier provider holding the state
-final randomNumberProvider = StateNotifierProvider(
-  (ref) => RandomNumberGenerator(),
-);
+final randomNumberProvider = NotifierProvider(RandomNumberGenerator.new);
 
 class RandomNumberApp extends StatelessWidget {
   const RandomNumberApp({super.key});