docs(readme): refactor README files to improve language link structure

- Combine language links into a single line in `README.md`
- Add links to English and Traditional Chinese README in `README.zh-cn.md`
- Combine language links into a single line in `README.zh-tw.md`

Signed-off-by: appleboy <appleboy.tw@gmail.com>

Author: appleboy

README.md

@@ -1,7 +1,6 @@
 # 🚀 SSH for GitHub Actions
 
-[繁體中文](./README.zh-tw.md)
-[简体中文](./README.zh-cn.md)
+[繁體中文](./README.zh-tw.md) | [简体中文](./README.zh-cn.md)
 
 [GitHub Action](https://github.com/features/actions) for executing remote SSH commands.
 

README.zh-cn.md

@@ -1,5 +1,7 @@
 # 🚀 用于 GitHub Actions 的 SSH
 
+[English](./README.md) | [繁體中文](./README.zh-tw.md)
+
 [GitHub Action](https://github.com/features/actions) 用于执行远程 SSH 命令。
 
 ![ssh workflow](./images/ssh-workflow.png)

README.zh-tw.md

@@ -1,7 +1,6 @@
 # 🚀 GitHub Actions 的 SSH
 
-[English](./README.md)
-[简体中文](./README.zh-cn.md)
+[English](./README.md) | [简体中文](./README.zh-cn.md)
 
 [GitHub Action](https://github.com/features/actions) 用於執行遠端 SSH 命令。