Fix linting CI pipeline job
Currently broken with errors like:
$ flake8 --select=F */python */options
Traceback (most recent call last):
File "/usr/bin/flake8", line 7, in <module>
from flake8.main.cli import main
File "/usr/lib/python2.7/site-packages/flake8/main/cli.py", line 4, in <module>
from flake8.main import application
File "/usr/lib/python2.7/site-packages/flake8/main/application.py", line 16, in <module>
from flake8.main import options
File "/usr/lib/python2.7/site-packages/flake8/main/options.py", line 3, in <module>
from flake8.main import debug
File "/usr/lib/python2.7/site-packages/flake8/main/debug.py", line 7, in <module>
import entrypoints
File "/usr/lib/python2.7/site-packages/entrypoints.py", line 19, in <module>
from backports import configparser
ImportError: cannot import name configparser