Fix cjio upgrade command in pipeline docs

README.md

@@ -83,7 +83,7 @@ LoD2 CityGML tiles can be converted to GLB per tile while preserving roof/wall s
    ```bash
    for f in work/cityjson/*.city.json; do
      base="$(basename "$f" .city.json)"
-     uv run cjio "$f" upgrade_version clean triangulate \
+     uv run cjio "$f" upgrade clean triangulate \
        save "work/cityjson_tri/${base}.tri.city.json"
    done
    ```