Update flake8 pinned versions.

We've learned this lesson the hard way in the past...

Change-Id: I02c75853234c16f3666185998202431cc7a4f2eb
Imported Translations from Transifex

Change-Id: Ic35873cb4e370a1ab5a1cc880752e261afe93621
Merge "Update flake8 pinned versions."