duration-str does not export its Result or Error type

[FrancisRussell]

I needed to write a wrapper around one of the parse functions to make it play nicely with clap's derive functionality, but I found I could not do this without introducing a dependency on anyhow since aliases for the error and result types used aren't available in the crate directly.

[baoyachi]

I‘m try refactor duration-str Result

[baoyachi]

@FrancisRussell Now, published new version, please use

[dependencies]
duration-str = "0.5.0"