Modify the README file

Signed-off-by: landwind <mamingshuai1@huawei.com>

+# 🚨 **重要提示 | IMPORTANT**
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+> **⚠️ 此代码仓已归档。新地址请访问 [flutter_wakelock](https://gitcode.com/openharmony-sig/flutter_wakelock)。| ⚠️ This repository has been archived. For the new address, please visit [flutter_wakelock](https://gitcode.com/openharmony-sig/flutter_wakelock).**
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 # Wakelock [![GitHub stars](https://img.shields.io/github/stars/creativecreatorormaybenot/wakelock.svg)](https://github.com/creativecreatorormaybenot/wakelock) [![Pub version](https://img.shields.io/pub/v/wakelock.svg)](https://pub.dev/packages/wakelock) [![Twitter Follow](https://img.shields.io/twitter/follow/creativemaybeno?label=Follow&style=social)](https://twitter.com/creativemaybeno)
 
 Wakelock is Flutter plugin that allows you to keep the device screen awake, i.e. prevent the screen

+# 🚨 **重要提示 | IMPORTANT**
+>
+> **⚠️ 此代码仓已归档。新地址请访问 [flutter_wakelock](https://gitcode.com/openharmony-sig/flutter_wakelock)。| ⚠️ This repository has been archived. For the new address, please visit [flutter_wakelock](https://gitcode.com/openharmony-sig/flutter_wakelock).**
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+---
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 # wakelock
 
 原始仓来源：https://github.com/creativecreatorormaybenot/wakelock