mutation issueSetAssignees($iid: String!, $assigneeUsernames: [String!]!, $projectPath: ID!) {
  issueSetAssignees(
    input: { iid: $iid, assigneeUsernames: $assigneeUsernames, projectPath: $projectPath }
  ) {
    issue {
      assignees {
        nodes {
          username
          id
          name
          webUrl
          avatarUrl
        }
      }
    }
  }
}
