Bump flake8 from 3.8.1 to 3.8.2

Bumps [flake8](https://gitlab.com/pycqa/flake8) from 3.8.1 to 3.8.2.
- [Release notes](https://gitlab.com/pycqa/flake8/tags)
- [Commits](https://gitlab.com/pycqa/flake8/compare/3.8.1...3.8.2)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements.txt

@@ -5,4 +5,4 @@ pytest==4.0.2
 pytest-cov==2.8.1
 pytest-sugar==0.9.3
 python-memcached==1.59
-flake8==3.8.1
+flake8==3.8.2