Update update-doc.yml

Author: LorenzoTettamanti

.github/workflows/update-doc.yml

@@ -21,9 +21,7 @@ jobs:
         run: |
           pip install mkdocs mkdocs-material
           pip install mkdocs-rss-plugin
-          pip install mkdocs-sitemap-plugin
-
-
+          
       - name: Build documentation
         run: mkdocs build
         working-directory: ./Doc