Update free-courses-en.md (#8748)

Adding Git course from GitKraken

courses/free-courses-en.md

@@ -576,6 +576,7 @@
 * [Bento Git Learning Track](https://bento.io/topic/git) (Bento)
 * [Bento GitHub Learning Track](https://bento.io/topic/github) (Bento)
 * [Complete Git and GitHub Tutorial](https://www.youtube.com/watch?v=apGV9Kg7ics) - Kunal Kushwaha
+* [Foundations of Git - Certification Course](https://learn.gitkraken.com/courses/git-foundations) - Axosoft (GitKraken) *(account or email address required)*
 * [Git](https://www.youtube.com/playlist?list=PLFBirL3MAv29Vy_L7MmV2QaZLvAadFPHR) - Gwendolyn Faraday
 * [Git & GitHub](https://www.youtube.com/playlist?list=PLWKjhJtqVAbkFiqHnNaxpOPhh9tSWMXIF) - Briana Marie, freeCodeCamp.org (YouTube)
 * [Git & GitHub](https://www.youtube.com/playlist?list=PLhW3qG5bs-L8OlICbNX9u4MZ3rAt5c5GG) - Raghav Pal, Automation Step by Step