[numpy] `torch.sigmoid` : promote integer inputs to float (#47551)
Summary:
Reference https://github.com/pytorch/pytorch/issues/42515
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47551
Reviewed By: ngimel
Differential Revision: D25211953
Pulled By: mruberry
fbshipit-source-id: 9174cda401aeba0fd585a4c9bda166dbcf64f42f
