added free courses (#6551)

* Update free-courses-en.md

Added free courses with their link for machine learning and data science.

* Update free-courses-en.md

Added free courses for data science and machine learning with correct alphabetical order.

* Update free-courses-en.md

Added free course for machine learning in alphabetical order.

* Update free-courses-en.md

* Update free-courses-en.md

courses/free-courses-en.md

@@ -271,6 +271,7 @@
 
 * [Advanced Data Mining with Weka MOOC](https://www.cs.waikato.ac.nz/ml/weka/mooc/advanceddataminingwithweka/)
 * [Data Analysis and Visualization](https://www.udacity.com/course/data-analysis-and-visualization--ud404) - Georgia Tech (Udacity)
+* [Data Analysis with Python: Zero to Pandas](https://jovian.ai/learn/data-analysis-with-python-zero-to-pandas) (Jovian)
 * [Data Analysis with R](https://www.udacity.com/course/data-analysis-with-r--ud651) - Facebook (Udacity)
 * [Data Cleaning by Rachael Tatman at Kaggle](https://www.kaggle.com/learn/data-cleaning)
 * [Data Mining with Weka MOOC](https://www.cs.waikato.ac.nz/ml/weka/mooc/dataminingwithweka/)
@@ -319,6 +320,7 @@
 * [Deep Learning for Natural Language Processing](http://cs224d.stanford.edu)
 * [Deep Learning Specialization](https://www.coursera.org/specializations/deep-learning) (coursera)
 * [Deep Learning with PyTorch](https://www.youtube.com/playlist?list=PLWKjhJtqVAbm3T2Eq1_KgloC7ogdXxdRa) - Aakash N. S., freeCodeCamp.org (YouTube)
+* [Deep Learning with Pytorch: Zero tp GANs](https://jovian.ai/learn/deep-learning-with-pytorch-zero-to-gans) (Jovian)
 * [Deep Multi-Task and Meta Learning](https://cs330.stanford.edu) - Chelsea Finn (Stanford University)
 * [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)
@@ -663,6 +665,7 @@
 * [Machine Learning Tutorial Python \| Machine Learning For Beginners](https://www.youtube.com/playlist?list=PLeo1K3hjS3uvCeTYTeyfe0-rN5r8zn9rw) - Dhaval Patel
 * [Machine Learning with Python - Youtube Playlist](https://www.youtube.com/playlist?list=PLZoTAELRMXVPBTrWtJkn3wWQxZkmTXGwe) - Krish Naik (YouTube)
 * [Machine Learning with Python by Saeed Aghabozorgi](https://cognitiveclass.ai/courses/machine-learning-with-python) (cognitiveclass.ai)
+* [Machine Learning with Python: Zero to GBMs](https://jovian.ai/learn/machine-learning-with-python-zero-to-gbms) (Jovian)
 * [Mathematics for Machine Learning - Linear Algebra](https://www.youtube.com/playlist?list=PLiiljHvN6z1_o1ztXTKWPrShrMrBLo5P3) - Imperial College London, Dr David Dye, Dr Sam Cooper
 * [Mathematics for Machine Learning - Multivariate Calclus](https://www.youtube.com/playlist?list=PLiiljHvN6z193BBzS0Ln8NnqQmzimTW23) - Imperial College London, Dr David Dye, Dr Sam Cooper
 * [Pattern Recognition and Machine Learning](https://www.microsoft.com/en-us/research/people/cmbishop/#!prml-book)