loongson/pypi: links for flatbuffers

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

loongson/pypi flatbuffers-20230107074622.tar.gz
loongson/pypi flatbuffers-20230107074616-py2.py3-none-any.whl
loongson/pypi flatbuffers-20220803092607-py2.py3-none-any.whl
loongson/pypi flatbuffers-20220803092605.tar.gz