Update README.md to confirm it works with python 3.7 and 3.8 and make the dir to paste into more specific

[tongclement]

OMG Thanks so much! It worked! This is a life saver. Just proposed a minor update to the readme to hopefully make it clear that it works with 3.7 and 3.8 too as some old stack overflow posts say it only works with 3.6. Please feel free to reject / rephrase this.