Request to update python futures library

[mateor]

The twitter.common libs depends on a pretty old version of futures, could you update to a more recent version?

This conflicts with the futures range required by some of our python libraries. boto3-1.3.0 is the most recent example that sent me here, it requires futures>=2.2.0,<4.0.0 for python 2.7. But this is not the first time I have seen it, just the first time I decided to try and solve the problem instead of working around it 😄

Boto3 requirements include the dep here.

The futures range above goes from 2.2.0 -> 4.0.0, but the most recent published version of futures is only 3.0.5, fyi.

I cloned t.c. and upgraded futures to the minimum viable upgrade (to 2.2.0) and will be sending a pull request along.