[be] ci: Remove unused promote workflow
This workflow was originally created to prmoote binaries but never
actually ended up being used since we kept the promotion process manual
to reduce the security risks.
Signed-off-by: Eli Uriegas <eliuriegas@fb.com>
Fixes #ISSUE_NUMBER
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76908
Approved by: https://github.com/janeyx99, https://github.com/mehtanirav
