Delete Travis CI config (#23788)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/23788
We be using Azure Pipelines now, matey!
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Differential Revision: D16648527
Pulled By: ezyang
fbshipit-source-id: d05326c4971fd392868f2a70aa0a9be9c7280f86
