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-dev.txt

@@ -4,7 +4,7 @@
 -r requirements-hyperopt.txt
 
 coveralls==2.0.0
-flake8==3.8.1
+flake8==3.8.2
 flake8-type-annotations==0.1.0
 flake8-tidy-imports==4.1.0
 mypy==0.770