Update sphinx.yml

Author: papadanku

.github/workflows/sphinx.yml

@@ -12,7 +12,7 @@ jobs:
     - name: Build HTML
       uses: ammaraskar/sphinx-action@master
     - name: Upload artifacts
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: html-docs
         path: docs/build/html/