build(deps): bump DavidAnson/markdownlint-cli2-action

Bumps the github-actions group with 1 update: [DavidAnson/markdownlint-cli2-action](https://github.com/davidanson/markdownlint-cli2-action).


Updates `DavidAnson/markdownlint-cli2-action` from 19 to 20
- [Release notes](https://github.com/davidanson/markdownlint-cli2-action/releases)
- [Commits](https://github.com/davidanson/markdownlint-cli2-action/compare/v19...v20)

---
updated-dependencies:
- dependency-name: DavidAnson/markdownlint-cli2-action
  dependency-version: '20'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
...

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

.github/workflows/ci.yml

@@ -33,7 +33,7 @@ jobs:
 
       - run: git ls-files -- '*.c' '*.h' | xargs clang-format --dry-run --Werror
 
-      - uses: DavidAnson/markdownlint-cli2-action@v19
+      - uses: DavidAnson/markdownlint-cli2-action@v20
 
       - run: taplo fmt --check