Improved error handling

[0Mayank]

Hi,

We use ripunzip as a crate in our app, and wanted to suggest propagating ripunzip errors using an enum instead of anyhow, it would allow us to handle them and show appropriate error messages to the user.

[adetaylor]

Thanks - yep, I'd be happy to accept a pull request to switch over to an enum (possibly using thiserror).

[0Mayank]

Great, I'm a bit busy this week, but I'll work on it and submit a pr soon.