Update README.md

Author: huhuhang

README.md

@@ -12,8 +12,6 @@ Jenkins is a free and open source automation server. Jenkins helps to automate t
 
 ## More Courses
 
-## More Courses
-
 - [Practice Linux Programming Courses](https://github.com/labex-labs/practice-linux-programming-courses)
 - [Practice Python Programming Courses](https://github.com/labex-labs/practice-python-programming-courses)
 - [Practice DevOps Programming Courses](https://github.com/labex-labs/practice-devops-programming-courses)