Summary: Currently, we bundle a specific version of `pep8` with Arcanist. Whilst maybe this made sense historically, as pointed out by @epriestley in D9412#6, there is no longer much point in doing so.
Test Plan: N/A
Reviewers: #blessed_reviewers, epriestley
Reviewed By: #blessed_reviewers, epriestley
Subscribers: talshiri, vrusinov, Korvin, epriestley
Differential Revision: https://secure.phabricator.com/D9430