Add pyupgrade

[stsewd]

Pyupgrade https://github.com/asottile/pyupgrade/

This will help us to remove all the code for python2 support, I just tested it with one fiile, and looks good.

[humitos]

Will it show errors or will it automatically change the code for us? Can we see an example of the result?

[stsewd]

It will change the code for us, here is an example of what it does https://github.com/asottile/pyupgrade/#implemented-features. I tested it on the projects/tasks.py file, and it really does a good job.

[humitos]

I'm closing this one since we already ran pyupgrade in org and com sites.