Make be_success rubocop check upstream

The following discussion from gitlab-ce!32091 should be addressed:

  • @.luke started a discussion: (+2 comments)

    @ck3g Have you considered contributing this to the rubocop-rspec gem itself, and then updating our Gemfile's version when it's merged? I think this has wider appeal that just GitLab, right?

Edited by 🤖 GitLab Bot 🤖