loongson/pypi: links for scikit-image

INFO: Because this project isn't in the mirror_whitelist, no releases from root/pypi are included.

loongson/pypi scikit_image-0.21.0-cp38-cp38-linux_loongarch64.whl
loongson/pypi scikit_image-0.19.3-cp37-cp37m-linux_loongarch64.whl