Function repos_slash_merge_upstream 

pub async fn repos_slash_merge_upstream(
    configuration: &Configuration,
    owner: &str,
    repo: &str,
    repos_merge_upstream_request: ReposMergeUpstreamRequest,
) -> Result<MergedUpstream, Error<ReposSlashMergeUpstreamError>>

Sync a branch of a forked repository to keep it up-to-date with the upstream repository.