replace 404 link

Author: Uyutaka

CONTRIBUTING.md

@@ -13,7 +13,7 @@ We welcome any type of contribution, not only code. You can help with
 
 ## Your First Contribution
 
-Working on your first Pull Request? 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? 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).
 
 ## Submitting code
 
@@ -64,4 +64,4 @@ Thank you to all our sponsors! (please ask your company to also support this ope
 <a href="https://opencollective.com/laravel-admin/sponsor/8/website" target="_blank"><img src="https://opencollective.com/laravel-admin/sponsor/8/avatar.svg"></a>
 <a href="https://opencollective.com/laravel-admin/sponsor/9/website" target="_blank"><img src="https://opencollective.com/laravel-admin/sponsor/9/avatar.svg"></a>
 
-<!-- This `CONTRIBUTING.md` is based on @nayafia's template https://github.com/nayafia/contributing-template -->
+<!-- This `CONTRIBUTING.md` is based on @nayafia's template https://github.com/nayafia/contributing-template -->