.github: Bump DavidAnson/markdownlint-cli2-action from 19.1.0 to 20.0.0

Bumps [DavidAnson/markdownlint-cli2-action](https://github.com/davidanson/markdownlint-cli2-action) from 19.1.0 to 20.0.0.
- [Release notes](https://github.com/davidanson/markdownlint-cli2-action/releases)
- [Commits](DavidAnson/markdownlint-cli2-action@05f3221...992badc)

---
updated-dependencies:
- dependency-name: DavidAnson/markdownlint-cli2-action
  dependency-version: 20.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/markdownlint.yml

@@ -11,6 +11,6 @@ jobs:
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
 
       - name: Run markdownlint
-        uses: DavidAnson/markdownlint-cli2-action@05f32210e84442804257b2a6f20b273450ec8265
+        uses: DavidAnson/markdownlint-cli2-action@992badcdf24e3b8eb7e87ff9287fe931bcb00c6e
         with:
           globs: "**/*.md"