[numpy] torch.lgamma: promote integer inputs to float (#50140)
Summary:
Reference: https://github.com/pytorch/pytorch/issues/42515
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50140
Reviewed By: mrshenli
Differential Revision: D25951094
Pulled By: mruberry
fbshipit-source-id: e53f1dbddff889710f05d43dbc9587382d3decb0
