Enable roullette review for version app

Why is this change being made?

• version roulette needs maintainer to be either be labeled backend or frontend, right now the only maintainers are labeled as maintainer and need to be maintainer backend or maintainer frontend for reviewer roulette to work

part of https://gitlab.com/gitlab-services/version-gitlab-com/issues/178

Does this MR meet the acceptance criteria?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what