loongson/pypi: links for gtsam-stubs

loongson/mirror gtsam-stubs-4.2.tar.gz
loongson/mirror gtsam_stubs-4.2-py3-none-any.whl
loongson/mirror gtsam-stubs-0.0.4.tar.gz
loongson/mirror gtsam_stubs-0.0.4-py3-none-any.whl
loongson/mirror gtsam_stubs-0.0.3-py3-none-any.whl
loongson/mirror gtsam-stubs-0.0.2.tar.gz
loongson/mirror gtsam_stubs-0.0.2-py3-none-any.whl
loongson/mirror gtsam-stubs-0.0.1.tar.gz
loongson/mirror gtsam_stubs-0.0.1-py3-none-any.whl