📝 Add UI designs base

Author: AlexV525

README-ZH.md

@@ -17,6 +17,8 @@ Language: [English](README.md) | 中文简体
 
 拍照及录制视频，请查看 example 详细用法，并前往 [wechat_camera_picker](https://fluttercandies.github.io/flutter_wechat_camera_picker/README-ZH.html) 。
 
+所有的界面细节基于 微信 7.x 版本，将在微信版本更新后随时进行跟进。
+
 ## 目录 🗂
 
 * [迁移指南](#迁移指南-)

README.md

@@ -21,6 +21,8 @@ and `provider` to help control the state of the picker.
 To take a photo or a video for assets, please check the detailed usage in the example, and head over to
 [wechat_camera_picker](https://fluttercandies.github.io/flutter_wechat_camera_picker/) .
 
+All UI designs are based on WeChat 7.x, and it will be updated following the WeChat update in anytime.
+
 ## Contributors ✨
 
 Many thanks to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):