[DataPipe] Adding output types to DataPipe interface file (#69647)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69647
cc VitalyFedyunin ejguan NivekT
Test Plan: Imported from OSS
Reviewed By: VitalyFedyunin
Differential Revision: D32989067
Pulled By: NivekT
fbshipit-source-id: 2c2e71e9e514e0d584affaa0b71b7b0d07a2ddbf
