updated egghead url (#4494)

Author: immanu10

content/docs/how-to-contribute.md

@@ -70,7 +70,7 @@ If you're only fixing a bug, it's fine to submit a pull request right away but w
 
 Working on your first Pull Request? You can learn how from this free video series:
 
-**[How to Contribute to an Open Source Project on GitHub](https://app.egghead.io/courses/how-to-contribute-to-an-open-source-project-on-github)**
+**[How to Contribute to an Open Source Project on GitHub](https://egghead.io/courses/how-to-contribute-to-an-open-source-project-on-github)**
 
 To help you get your feet wet and get you familiar with our contribution process, we have a list of **[good first issues](https://github.com/facebook/react/issues?q=is:open+is:issue+label:"good+first+issue")** that contain bugs that have a relatively limited scope. This is a great place to get started.