chore(README): gitter url to matrix (#4520)

README.md

@@ -8,7 +8,7 @@
     <a href="https://github.com/neoclide/coc.nvim/actions"><img alt="Actions" src="https://img.shields.io/github/actions/workflow/status/neoclide/coc.nvim/ci.yml?style=flat-square&branch=master"></a>
       <a href="https://codecov.io/gh/neoclide/coc.nvim"><img alt="Codecov Coverage Status" src="https://img.shields.io/codecov/c/github/neoclide/coc.nvim.svg?style=flat-square"></a>
     <a href="doc/coc.txt"><img alt="Doc" src="https://img.shields.io/badge/doc-%3Ah%20coc.txt-brightgreen.svg?style=flat-square"></a>
-    <a href="https://gitter.im/neoclide/coc.nvim"><img alt="Gitter" src="https://img.shields.io/gitter/room/neoclide/coc.nvim.svg?style=flat-square"></a>
+    <a href="https://matrix.to/#/#coc.nvim:matrix.org"><img alt="Gitter" src="https://img.shields.io/gitter/room/neoclide/coc.nvim.svg?style=flat-square"></a>
   </p>
 </p>
 
@@ -468,8 +468,8 @@ Try these steps if you experience problems with coc.nvim:
 
 - Have a question? Start a discussion on [GitHub Discussions](https://github.com/neoclide/coc.nvim/discussions).
 - File a bug in [GitHub Issues](https://github.com/neoclide/coc.nvim/issues).
-- Chat with us on [Gitter](https://gitter.im/neoclide/coc.nvim).
-- 中文用户请到 [中文 gitter](https://gitter.im/neoclide/coc-cn) 讨论
+- Chat with us on [Gitter](https://matrix.to/#/#coc.nvim:matrix.org).
+- 中文用户请到 [中文 gitter](https://matrix.to/#/#neoclide_coc-cn:gitter.im) 讨论
 
 ## Backers