The utf-8 crate is unmaintained

[SimonSapin]

This is to let you know that I’ve archived https://github.com/SimonSapin/rust-utf8, the source repository for https://crates.io/crates/utf-8 which you depend on. No action is required as I’m not planning the yank the crate, and it’s small enough that it’s possibly bug-free. However if at some point you still need changes in it, you’ll be better off copying relevant code into your own repository.