Add torch.__config__.show(), reporting detailed version of all libraries. (#18579)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18579
ghimport-source-id: 65124c95e49423de4ad1008c65e75057fea09b94
Differential Revision: D14778507
Pulled By: ezyang
fbshipit-source-id: 1e4bb79f4800a116ce8fb7af2fefbd34da8d102c
