Add Resource to free-courses-en.md#deep-learning (#5087)

* Fix #4099

* Remove Redundant Route in URL

free-courses-en.md

@@ -228,6 +228,7 @@
 * [Deep Learning for Natural Language Processing](http://cs224d.stanford.edu)
 * [Deep Learning Specialization](https://www.coursera.org/specializations/deep-learning) (coursera)
 * [Deep Reinforcement Learning](http://rail.eecs.berkeley.edu/deeprlcourse/) - Sergey Levine
+* [Exploring Fairness in Machine Learning for International Development](https://ocw.mit.edu/resources/res-ec-001-exploring-fairness-in-machine-learning-for-international-development-spring-2020) - Dr. Richard Fletcher, Prof. Daniel Frey, Dr. Mike Teodorescu, Amit Gandhi, Audace Nakeshimana (MIT OpenCourseWare)
 * [Intro to Deep Learning](https://www.kaggle.com/learn/intro-to-deep-learning) - Ryan Holbrook
 * [Introduction to Reinforcement learning with David Silver](https://www.youtube.com/playlist?list=PLqYmG7hTraZBiG_XpjnPrSNw-1XQaM_gB) - David Silver
 * [MIT 6.S094: Deep Learning for Self-Driving Cars](https://selfdrivingcars.mit.edu)