Add code comment for pin

.github/workflows/main.yml

@@ -27,6 +27,7 @@ jobs:
       - name: Install Python dependencies
         run: |
           python -m pip install --upgrade pip
+          # Later versions of mkdocs giving build error remated to a missing import for 'templates'.
           pip install mkdocs==1.5.3 mkdocs-material mike mkdocs-git-authors-plugin mkdocs-redirects mkdocs-git-revision-date-localized-plugin pymdown-extensions git+https://gitlab.com/blacs30/mkdocs-edit-url.git
       - name: Setup PHP
         uses: shivammathur/setup-php@v2