chore: replace double quotes to single quotes (https://github.com/flutter/flutter/blob/master/docs/contributing/Style-guide-for-Flutter-repo.md#prefer-single-quotes-for-strings)

lib/setting_page.dart

@@ -35,12 +35,12 @@ class _SettingPageState extends State<SettingPage> {
               ..removeCurrentSnackBar()
               ..showSnackBar(
                 const SnackBar(
-                  content: Text("功能暂未开发, 敬请期待~"),
+                  content: Text('功能暂未开发, 敬请期待~'),
                   duration: Duration(seconds: 2),
                 ),
               );
           },
-          child: const Text("检查更新"),
+          child: const Text('检查更新'),
         ),
       ],
     );