Add md linting to action

Author: CoMPaTech

.github/workflows/verify.yml

@@ -153,6 +153,10 @@ jobs:
         run: |
           . venv/bin/activate
           pre-commit run --show-diff-on-failure --color=always --all-files --hook-stage manual pylint
+      - name: Lint markdown files
+        run: |
+          . venv/bin/activate
+          pre-commit run --show-diff-on-failure --color=always --all-files --hook-stage manual markdownlint
 
   prepare-test-cache:
     runs-on: ubuntu-latest