Update actions/upload-artifact action to v6 (#9227)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/docs.yml

@@ -39,7 +39,7 @@ jobs:
       - name: Generate Docs
         run: ./test_docs.sh
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: docs
           path: site/