* Adding AI course in free-courses-en.md

Artificial Intelligence on Google Cloud Platform Youtube Playlist

* Update courses/free-courses-en.md

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