Bump mypy from 1.8.0 to 1.9.0

Bumps [mypy](https://github.com/python/mypy) from 1.8.0 to 1.9.0.
- [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
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements-dev.txt

@@ -24,7 +24,7 @@ looseversion==1.3.0 ; python_version >= '3.5'
 
 mccabe==0.7.0 ; python_version >= '3.6'
 
-mypy==1.8.0
+mypy==1.9.0
 
 mypy-extensions==1.0.0 ; python_version >= '3.5'