Update flake8 requirement from ~4 to ~5

Updates the requirements on [flake8](https://github.com/pycqa/flake8) to permit the latest version.
- [Commits](PyCQA/flake8@4.0.0...5.0.4)

---
updated-dependencies:
- dependency-name: flake8
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

pyproject.toml

@@ -40,7 +40,7 @@ all = ["zeep", "ipython", "orjson"]
 
 [tool.poetry.dev-dependencies]
 black = "~22"
-flake8 = "~4"
+flake8 = "~5"
 isort = "~5"
 mkdocs-material = "~8"
 mypy = "~0"