Add DevOps Course (#7365)

* Add DevOps Course

* Update courses/free-courses-en.md

Co-authored-by: Eric Hellman <eric@hellman.net>

* Update courses/free-courses-en.md

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-en.md

Co-authored-by: Eric Hellman <eric@hellman.net>

Co-authored-by: Eric Hellman <eric@hellman.net>
Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

courses/free-courses-en.md

@@ -383,6 +383,7 @@
 ### DevOps
 
 * [DevOps Bootcamp](https://www.youtube.com/playlist?list=PL9gnSGHSqcnoqBXdMwUTRod4Gi3eac2Ak) - Kunal Kushwaha
+* [Intro to DevOps](https://www.udacity.com/course/intro-to-devops--ud611) - Karl Krueger, Dwayne Lessner, Gundega Dekena (Udacity)
 
 
 ### Docker