[package] add some docs describing how to debug dependencies (#65704)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65704
As title.
Test Plan: Imported from OSS
Reviewed By: tugsbayasgalan
Differential Revision: D31209866
Pulled By: suo
fbshipit-source-id: 4c8ec1d5418ea75b71c4b9a498b86f0ef5383544
