Replace deleted course with its video playlist

README.md

@@ -339,7 +339,7 @@ Courses | Duration | Effort | Prerequisites
 [Introduction to Haskell](https://www.seas.upenn.edu/~cis194/fall16/)| 14 weeks | - | -
 [Learn Prolog Now!](https://www.let.rug.nl/bos/lpn//lpnpage.php?pageid=online) ([alternative](https://github.com/ossu/computer-science/files/6085884/lpn.pdf))*| 12 weeks | - | -
 [Software Debugging](https://www.udacity.com/course/software-debugging--cs259)| 8 weeks | 6 hours/week | Python, object-oriented programming
-[Software Testing](https://www.udacity.com/course/software-testing--cs258) | 4 weeks | 6 hours/week | Python, programming experience
+[Software Testing](https://www.youtube.com/playlist?list=PLAwxTw4SYaPkWVHeC_8aSIbSxE_NXI76g) | 4 weeks | 6 hours/week | Python, programming experience
 
 (*) book by Blackburn, Bos, Striegnitz (compiled from [source](https://github.com/LearnPrologNow/lpn), redistributed under [CC license](https://creativecommons.org/licenses/by-sa/4.0/))