chore(deps): update actions/upload-pages-artifact action to v4

Author: renovate[bot]

.github/workflows/docs.yml

@@ -47,7 +47,7 @@ jobs:
           cp docs/README.md site/llms.txt
 
       - name: Upload Pages artifact
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@v4
         with:
           path: site/