Bump flake8 from 3.8.2 to 3.8.3

Bumps [flake8](https://gitlab.com/pycqa/flake8) from 3.8.2 to 3.8.3.
- [Release notes](https://gitlab.com/pycqa/flake8/tags)
- [Commits](https://gitlab.com/pycqa/flake8/compare/3.8.2...3.8.3)

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

setup.py

@@ -11,7 +11,7 @@
     ],
     "docs": ["marshmallow-sqlalchemy>=0.13.0", "Sphinx==3.0.4", "sphinx-issues==1.2.0"],
     "lint": [
-        "flake8==3.8.2",
+        "flake8==3.8.3",
         'flake8-bugbear==20.1.4; python_version >= "3.5"',
         "pre-commit~=2.4",
     ],