update links to courses

Hey @ashishpatel26 

I am stepping out of Udemy slowly slowly, and hence, I suggest updating the links of these courses to were they will live in the coming months.

I appreciate your support :)

Author: solegalli

README.md

@@ -173,18 +173,10 @@ Below is a list of methods currently implemented in the repo.
 
 https://www.trainindata.com/p/feature-engineering-for-machine-learning
 
-or
-
-https://www.udemy.com/feature-engineering-for-machine-learning/
-
 - Feature Selection for Machine Learning online course
 
 https://www.trainindata.com/p/feature-selection-for-machine-learning
 
-or
-
-https://www.udemy.com/feature-selection-for-machine-learning
-
 - JMLR Special Issue on Variable and Feature Selection
 
 http://jmlr.org/papers/special/feature03.html