Function holochain::prelude::ffs::canonicalize

pub async fn canonicalize<P>(
    path: P
) -> impl Future<Output = Result<PathBuf, IoError>>where
    P: Clone + AsRef<Path>,

Wrap dunce::canonicalize, since std::fs::canonicalize has problems for Windows (see https://docs.rs/dunce/1.0.1/dunce/index.html)