Function sync_issue_dependencies 

pub async fn sync_issue_dependencies(
    backend: &dyn ExternalBackend,
    store: &TaskStore,
    task_id: i64,
    repo: &str,
    issue_number: Option<i64>,
    body: &str,
) -> Result<SyncOutcome>

Replace one issue’s dependency rows from GitHub, or from the body when GitHub cannot answer.