Pull Requests
  Awaiting Maintainer Response
    maintainer approves -> Approved
    maintainer requests changes -> Awaiting Contributor Response
    maintainer rejects -> Closed
    maintainer finishes PR -> Approved
  Awaiting Contributor Response
    contributor updates -> Awaiting Maintainer Response
    no timely contributor update -> Awaiting Maintainer Response
  Approved
    maintainer merges -> Merged
    contributor updates -> Awaiting Maintainer Response
  Merged
  Closed