Only allow multiple reviewers in paid tiers
Problem to solve
For best alignment with out tier strategy, multiple reviewers should be available only in Starter+ tiers.
Further information
Currently, multiple assignees is available in Starter+ tier https://docs.gitlab.com/ee/user/project/merge_requests/getting_started.html#multiple-assignees-starter
Proposal
Allow for a single reviewer in free tier and multiple reviewers in Starter+ tiers.
Edited by Pedro Moreira da Silva