Bump mypy from 1.5.1 to 1.6.0

Bumps [mypy](https://github.com/python/mypy) from 1.5.1 to 1.6.0.
- [Commits](python/mypy@v1.5.1...v1.6.0)

---
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 @@
 -r ci.txt
 -r doc.txt
-mypy==1.5.1
+mypy==1.6.0
 pre-commit==3.4.0
 pytest-sugar==0.9.7