Update free-courses-ko.md (#7209)

* Update free-courses-ko.md

* update PHP course

update PHP course

courses/free-courses-ko.md

@@ -211,6 +211,7 @@
 
 ### PHP
 
+* [PHP](https://youtube.com/playlist?list=PLuHgQVnccGMDzq8zAwEY5lvwDWXWTZjB6) - 생활코딩
 * [PHP 프로그래밍](https://www.youtube.com/playlist?list=PLYNsYgev6U96jzS7AjBn5p7i_owJHqfyW)