ci(deps): bump DavidAnson/markdownlint-cli2-action from 21 to 22

Update markdownlint-cli2-action to v22.

Changes:
- markdownlint-cli2 updated to v0.20.0
- markdownlint updated to v0.40.0

All CI checks passing.

Author: dependabot[bot]

.github/workflows/docs.yml

@@ -38,7 +38,7 @@ jobs:
       - uses: actions/checkout@v6
 
       - name: markdownlint
-        uses: DavidAnson/markdownlint-cli2-action@v21
+        uses: DavidAnson/markdownlint-cli2-action@v22
         with:
           globs: |
             **/*.md