Fix #44: it now runs on M1 macOS using tensorflow-metal

[giodegas]

Thank's to this tutorial:

https://makeoptim.com/en/deep-learning/tensorflow-metal

and adapting the requirements.txt and setup.cfg install file, it is now ok.

Fix #44 .

[giodegas]

Forgot the 5.4 section title

[giodegas]

fix nlpia typo in the ReadMe.md