Function create_task 

pub fn create_task(
    repo_root: &Path,
    delegator: &str,
    delegatee: &str,
    title: &str,
    description: &str,
    priority: TaskPriority,
    scope: Vec<String>,
    deadline: Option<String>,
    ucan_proof: Option<String>,
) -> Result<DelegatedTask, LitError>

Create a new delegated task