docs: update README.MD (#652)

README.MD

@@ -9,9 +9,9 @@
 <a href="https://t.me/run_ikaros"><img alt="Telegram" src="https://img.shields.io/badge/Telegram-2CA5E0?style=flat-squeare&logo=telegram&logoColor=white" /></a>
 <a href="http://qm.qq.com/cgi-bin/qm/qr?_wv=1027&k=78drHnTdkaGQHwAkt1eEU3JpxBfUeuPx&authKey=dvZ0CdZjiX36wKiDlDF0qKVcEDe7SNXfL%2BllKTIf%2FgiXNHwlWqTmlXTs%2BtLnB1un&noverify=0&group_code=413528874"><img alt="Telegram" src="https://img.shields.io/badge/413528874-2CA5E0?logo=tencent-qq&logoColor=white" /></a>
 <br />
-<a href="https://app.codecov.io/github/ikaros-dev/ikaros"><img alt="code coverage" src="https://img.shields.io/codecov/c/github/ikaros-dev/ikaros/master?style=flat-square" /></a>
+<a href="https://app.codecov.io/github/ikaros-dev/ikaros"><img alt="code coverage" src="https://img.shields.io/codecov/c/github/ikaros-dev/ikaros/main?style=flat-square" /></a>
 <a href="https://github.com/ikaros-dev/ikaros/commits"><img alt="GitHub last commit" src="https://img.shields.io/github/last-commit/ikaros-dev/ikaros.svg?style=flat-square" /></a>
-<a href="https://github.com/ikaros-dev/ikaros/actions"><img alt="GitHub workflow build status" src="https://img.shields.io/github/actions/workflow/status/ikaros-dev/ikaros/ikaros-server-ci.yml?branch=master&style=flat-square" /></a>
+<a href="https://github.com/ikaros-dev/ikaros/actions"><img alt="GitHub workflow build status" src="https://img.shields.io/github/actions/workflow/status/ikaros-dev/ikaros/ikaros-server-ci.yml?branch=main&style=flat-square" /></a>
 <br />
 <a href="https://github.com/ikaros-dev/ikaros/releases"><img alt="Github Releases" src="https://img.shields.io/github/v/release/ikaros-dev/ikaros?include_prereleases&style=flat-square" /></a>
 <a href="https://github.com/ikaros-dev/ikaros/stargazers"><img alt="GitHub Stargazers" src="https://img.shields.io/github/stars/ikaros-dev/ikaros.svg?style=flat-square&label=Stars&logo=github" /></a>
@@ -44,7 +44,7 @@
 
 # 许可证
 
-<a href="https://github.com/ikaros-dev/ikaros/blob/master/LICENSE"><img alt="LICENSE" src="https://img.shields.io/github/license/ikaros-dev/ikaros?style=flat-square" /></a>
+<a href="https://github.com/ikaros-dev/ikaros/blob/main/LICENSE"><img alt="LICENSE" src="https://img.shields.io/github/license/ikaros-dev/ikaros?style=flat-square" /></a>
 
 Ikaros 使用 AGPL-v3.0 协议开源，请遵守开源协议。