adding some data science courses (#5636)

courses/free-courses-en.md

@@ -226,6 +226,8 @@
 * [Data Science interview questions](https://www.youtube.com/playlist?list=PLZoTAELRMXVPkl7oRvzyNnyj1HS4wt2K-) - Krish Naik
 * [Data Visualization by Alexis Cook at Kaggle](https://www.kaggle.com/learn/data-visualization)
 * [Datavis 2020](https://www.youtube.com/playlist?list=PL9yYRbwpkykuK6LSMLH3bAaPpXaDUXcLV) - Curran Kelleher
+* [IBM AI Engineering Professional Certificate](https://www.coursera.org/professional-certificates/ai-engineer) (Coursera)
+* [IBM Data Science Professional Certificate](https://www.coursera.org/professional-certificates/ibm-data-science) (Coursera)
 * [Introduction to Data Science in Python](https://www.coursera.org/learn/python-data-analysis) - Christopher Brooks (Coursera)
 * [More Data Mining with Weka MOOC](https://www.cs.waikato.ac.nz/ml/weka/mooc/moredataminingwithweka/)
 * [The Analytics Edge](https://www.edx.org/course/analytics-edge-mitx-15-071x-3)