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[bot] <support@github.com>

Author: dependabot[bot]

poetry.lock

@@ -18,7 +18,7 @@ importlib_metadata = {version = "^1.6.0", python = "<3.8"}
 pytest = "^5.4.3"
 coverage = {extras = ["toml"], version = "^5.0.3"}
 black = "^19.10b0"
-flake8 = "^3.8.2"
+flake8 = "^3.8.3"
 flake8-bandit = "^2.1.2"
 flake8-black = "^0.2.0"
 flake8-bugbear = "^20.1.4"