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>

Author: dependabot-preview[bot]

dev-requirements.txt

@@ -13,7 +13,7 @@ doc8==0.8.1
 dodgy==0.2.1  # Look for uploaded secrets
 flake8-commas==2.0.0  # Require silicon valley commas
 flake8-quotes==3.2.0  # Require single quotes
-flake8==3.8.2  # Lint
+flake8==3.8.3  # Lint
 freezegun==0.3.15
 isort==4.3.21  # Lint imports
 mypy==0.780  # Type checking