Bump mypy from 1.6.1 to 1.8.0

Bumps [mypy](https://github.com/python/mypy) from 1.6.1 to 1.8.0.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.6.1...v1.8.0)

---
updated-dependencies:
- dependency-name: mypy
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

requirements.dev.txt

@@ -1,5 +1,5 @@
 flake8==6.0.0
 httpx==0.24.1
-mypy==1.6.1
+mypy==1.8.0
 mypy-extensions==1.0.0
 uvicorn==0.23.2