Comment 7 for bug 1799721

Here's some info about why StarlingX was hit, but standard openstack projects were not.

Typically in the tox.ini files the pep8 section looks something like this:

deps =
    hacking
    flake8-bugbear
    flake8

whereas conventional openstack projects probably just have:

deps =
    hacking

hacking has a dependency on flake8
  flake8<2.7.0,>=2.6.0 # MIT
so it pulls in 2.6.2

flake8-bugbear conflicts with this
   install_requires=["flake8 >= 3.0.0"

specifying flake8 as its own line in the deps section seems to bypass the conflicting constraints that those other 2 components impose on one another.