Fix link in README (#1024)

Author: sajadtorkamani

CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 Thanks for being willing to contribute! 🙏
 
-**Working on your first Pull Request (PR)?** You can learn how from this _free_ series [How to Contribute to an Open Source Project on GitHub](https://egghead.io/series/how-to-contribute-to-an-open-source-project-on-github)
+**Working on your first Pull Request (PR)?** You can learn how from this _free_ series [How to Contribute to an Open Source Project on GitHub](https://app.egghead.io/playlists/how-to-contribute-to-an-open-source-project-on-github)
 
 ## Open issues