build: add markdown linting to workflow

.github/workflows/build.yml

@@ -282,6 +282,16 @@ jobs:
       - name: Scan for vulnerabilities
         run: govulncheck ./...
 
+      - name: Check Markdown format
+        uses: DavidAnson/markdownlint-cli2-action@v20
+        with:
+          globs: |
+            CONTRIBUTING.md
+            MAINTAINERS.md
+            README.md
+            RELEASE.md
+            docs/content/{authors,bugs,changelog,docs,downloads,faq,filtering,gui,install,licence,overview,privacy}.md
+
       - name: Scan edits of autogenerated files
         run: bin/check_autogenerated_edits.py 'origin/${{ github.base_ref }}'
         if: github.event_name == 'pull_request'