Bump mypy from 2.3 to 2.3.1

Bumps [mypy](https://github.com/python/mypy) from 2.3 to 2.3.1.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v2.3.0...v2.3.1)

---
updated-dependencies:
- dependency-name: mypy
  dependency-version: 2.3.1
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

pyproject.toml

@@ -68,7 +68,7 @@ dependencies = [
   "tomli; python_version<'3.11'",
 ]
 optional-dependencies.dev = [
-  "mypy==2.3",
+  "mypy==2.3.1",
   "tomli",     # Needed even on 3.11+ for typechecking with mypy
   "tox",
 ]