Update about Python lecture

[jstac]

This lecture needs a bit of an update.

https://python.quantecon.org/about_py.html

The figures could be updated and we might include this link:

https://spectrum.ieee.org/computing/software/the-top-programming-languages-2019

Note the discussion there as to why Python is popular. It's more up to date than our discussion.

[jstac]

https://www.zdnet.com/article/tech-jobs-python-programming-language-and-aws-skills-demand-has-exploded/