Bump markdownlint-cli2-action from v19 to v23 (#15)

Picks up markdownlint-cli2 0.22.1, markdownlint 0.40.0, and Node.js 24
support.

Signed-off-by: Sergio Arroutbi <sarroutb@redhat.com>

Author: sarroutbi

.github/workflows/markdown-lint.yaml

@@ -34,7 +34,7 @@ jobs:
           echo "$CHANGED"
           echo "lintable=$(cat "$GITHUB_OUTPUT" | grep lintable | cut -d= -f2)"
 
-      - uses: DavidAnson/markdownlint-cli2-action@v19
+      - uses: DavidAnson/markdownlint-cli2-action@v23
         if: steps.filter.outputs.lintable == 'true'
         with:
           globs: '**/*.md'