chore(deps-dev): bump mypy from 1.19.1 to 1.20.0 in the minor group

Bumps the minor group with 1 update: [mypy](https://github.com/python/mypy).


Updates `mypy` from 1.19.1 to 1.20.0
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.19.1...v1.20.0)

---
updated-dependencies:
- dependency-name: mypy
  dependency-version: 1.20.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: minor
...

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

Author: dependabot[bot]

pyproject.toml

@@ -81,7 +81,7 @@ dev-mkdocs = [
   "frequenz-repo-config[lib] == 0.14.0",
 ]
 dev-mypy = [
-  "mypy == 1.19.1",
+  "mypy == 1.20.0",
   "grpc-stubs == 1.53.0.6",
   "pandas-stubs == 3.0.0.260204",
   "types-Markdown == 3.10.2.20260211",