Add "Learn Python 3" (#9196)

* Add "Learn Python 3"

* Update free-programming-books-langs.md

books/free-programming-books-langs.md

@@ -1956,6 +1956,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Introduction to Python for Econometrics, Statistics and Numerical Analysis](https://www.kevinsheppard.com/files/teaching/python/notes/python_introduction_2020.pdf) - Kevin Sheppard (PDF) (3.8)
 * [Introduction to Scientific Programming with Python](https://library.oapen.org/bitstream/id/56d27e73-e92a-4398-8198-239be7aacc93/2020_Book_IntroductionToScientificProgra.pdf) - Joakim Sundnes (PDF)
 * [Invent Your Own Computer Games With Python](https://inventwithpython.com/invent4thed/) - Al Sweigart (3.4)
+* [Learn Python 3](https://github.com/animator/learn-python) - Ankit Mahato (PDF, HTML, Markdown)
 * [Learn Python, Break Python](http://learnpythonbreakpython.com)
 * [Learn Python in Y minutes](https://learnxinyminutes.com/docs/python/) - LearnXinYMinutes (HTML)
 * [Learn Python Programming, Second Edition](https://www.packtpub.com/free-ebooks/learn-python-programming-second-edition) - Fabrizio Romano (Packt account *required*)