[Doc] Add Korean translation for README.md (#2040)

### What problem does this PR solve?

Add Korean translation for the `README.md` file.
This translation aims to accurately convey the meaning of the original
document.

### Type of change

- [x] Documentation Update

README.md

@@ -7,7 +7,8 @@
 <p align="center">
   <a href="./README.md">English</a> |
   <a href="./README_zh.md">简体中文</a> |
-  <a href="./README_ja.md">日本語</a>
+  <a href="./README_ja.md">日本語</a> |
+  <a href="./README_ko.md">한국어</a>
 </p>
 
 <p align="center">