CI: Switch to DavidAnson/markdownlint-cli2-action for markdown linting (#463)

Author: nicoburns

.github/workflows/ci.yml

@@ -163,12 +163,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-        with:
-          # Full git history is needed to get a proper list of changed files within `super-linter`
-          fetch-depth: 0
       - name: Run Markdown Lint
-        uses: docker://ghcr.io/github/super-linter:slim-v4
-        env:
-          VALIDATE_ALL_CODEBASE: true
-          VALIDATE_MARKDOWN: true
-          DEFAULT_BRANCH: master
+        uses: DavidAnson/markdownlint-cli2-action@v9
+        with:
+          globs: '**/*.md'