Update upload-artifact action to v4

Author: mojnomiya

.github/workflows/docs.yml

@@ -29,7 +29,7 @@ jobs:
           sphinx-build -W -b html -d _build/doctrees . _build/html
 
       - name: Upload documentation
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: documentation
           path: docs/_build/html/