remove broken API references in documentation

- disable API doc for now.
- update GitHub action `upload-pages-artifact`

Co-authored-by: HeinrichAD <[email protected]>

Author: unru-jo

.github/workflows/main.yml

@@ -108,7 +108,7 @@ jobs:
             echo "::warning title=Invalid file permissions automatically fixed::$line"
           done
       - name: Upload Pages artifact
-        uses: actions/upload-pages-artifact@v2
+        uses: actions/upload-pages-artifact@v3
         with:
           path: site
 

mkdocs.yml

@@ -10,7 +10,7 @@ repo_url: https://github.com/DLR-KI/fl-demonstrator-frontend
 
 nav:
   - Home: index.md
-  - API: "api/index.html"
+#  - API: "api/index.html"
 
 theme:
   name: material