chore(deps-dev): bump types-markdown

Bumps [types-markdown](https://github.com/python/typeshed) from 3.10.2.20260408 to 3.10.2.20260518.
- [Commits](https://github.com/python/typeshed/commits)

---
updated-dependencies:
- dependency-name: types-markdown
  dependency-version: 3.10.2.20260518
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

pyproject.toml

@@ -85,7 +85,7 @@ dev-mypy = [
   "mypy == 2.1.0",
   "grpc-stubs == 1.53.0.6",
   "pandas-stubs == 3.0.3.260530",
-  "types-Markdown == 3.10.2.20260408",
+  "types-Markdown == 3.10.2.20260518",
   "types-protobuf == 7.34.1.20260518",
   # For checking the noxfile, docs/ script, and tests
   "frequenz-client-electricity-trading[dev-mkdocs,dev-noxfile,dev-pytest]",