Update mypy requirement from ~1.8 to ~1.9

Updates the requirements on [mypy](https://github.com/python/mypy) to permit the latest version.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.8.0...1.9.0)

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

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

pyproject.toml

@@ -13,7 +13,7 @@ requests = "~2.31"
 deepl = "^1.2.1"
 
 [tool.poetry.dev-dependencies]
-mypy = "~1.8"
+mypy = "~1.9"
 pre-commit = "~3.6"
 pylint = "~3.1"
 pytest = "~8.1"