.github: Adding configuration for backwards_compat (#64204)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64204
Adds backwards_compat to our existing test matrix for github actions
Signed-off-by: Eli Uriegas <eliuriegas@fb.com>
cc ezyang seemethere malfet walterddr lg20987 pytorch/pytorch-dev-infra
Test Plan: Imported from OSS
Reviewed By: malfet
Differential Revision: D30646764
Pulled By: seemethere
fbshipit-source-id: f0da6027e29fab03aff058cb13466fae5dcf3678
