Bump markdownlint-cli2 from 0.20.0 to 0.21.0 (#500)

Bumps [markdownlint-cli2](https://github.com/DavidAnson/markdownlint-cli2) from 0.20.0 to 0.21.0.
- [Changelog](https://github.com/DavidAnson/markdownlint-cli2/blob/main/CHANGELOG.md)
- [Commits](DavidAnson/markdownlint-cli2@v0.20.0...v0.21.0)

---
updated-dependencies:
- dependency-name: markdownlint-cli2
  dependency-version: 0.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -57,7 +57,7 @@
     "eslint-plugin-prettier": "^5.5.4",
     "globals": "^17.0.0",
     "jest": "^30.0.5",
-    "markdownlint-cli2": "^0.20.0",
+    "markdownlint-cli2": "^0.21.0",
     "markdownlint-cli2-formatter-pretty": "^0.0.9"
   },
   "prettier": "@github/prettier-config"