[cupertino_icons] Add example to cupertino icons (#5312)

## Description of PR:

Adding an example app to showcase the usage of `cupertino_icons`. This addition will also increase the pub points of the package and will be helpful for other developers to quickly find relevant examples.

Fixes flutter/flutter#137682

third_party/packages/cupertino_icons/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 1.0.7
 
+* Adds example.md file to display usage.
 * Updates minimum supported SDK version to Flutter 3.10/Dart 3.0.
 
 ## 1.0.6

third_party/packages/cupertino_icons/example/example.md

@@ -0,0 +1,14 @@
+<?code-excerpt path-base="../test"?>
+
+This package is used via [`CupertinoIcons`](https://api.flutter.dev/flutter/cupertino/CupertinoIcons-class.html):
+
+<?code-excerpt "cupertino_icons_test.dart (CupertinoIcon)"?>
+```dart
+const Icon icon = Icon(
+  CupertinoIcons.heart_fill,
+  color: Colors.pink,
+  size: 24.0,
+);
+```
+
+For a list of all icons, see [`CupertinoIcons`](https://api.flutter.dev/flutter/cupertino/CupertinoIcons-class.html#constants) [class documentation constants](https://api.flutter.dev/flutter/cupertino/CupertinoIcons-class.html#constants).

third_party/packages/cupertino_icons/pubspec.yaml

@@ -3,11 +3,17 @@ name: cupertino_icons
 description: Default icons asset for Cupertino widgets based on Apple styled icons
 repository: https://github.com/flutter/packages/tree/main/third_party/packages/cupertino_icons
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+cupertino_icons%22
-version: 1.0.6
+version: 1.0.7
 
 environment:
   sdk: ">=3.0.0 <4.0.0"
 
+dev_dependencies:
+  flutter:
+    sdk: flutter
+  flutter_test:
+    sdk: flutter
+
 flutter:
   fonts:
     - family: CupertinoIcons

third_party/packages/cupertino_icons/test/cupertino_icons_test.dart

@@ -0,0 +1,35 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// This test file is primarily here to serve as a source for code excerpts.
+library;
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets(
+    'Cupertino Icon Test',
+    (WidgetTester tester) async {
+      // #docregion CupertinoIcon
+      const Icon icon = Icon(
+        CupertinoIcons.heart_fill,
+        color: Colors.pink,
+        size: 24.0,
+      );
+      // #enddocregion CupertinoIcon
+
+      await tester.pumpWidget(
+        const MaterialApp(
+          home: Scaffold(
+            body: icon,
+          ),
+        ),
+      );
+
+      expect(find.byType(Icon), findsOne);
+    },
+  );
+}