Dinghy used to be deployed on the dinghy name on crates.io, we've since moved to cargo-dinghy to have the same name as the binary.
The use of the dinghy crate is deprecated, use cargo-dinghy instead.
Install it with the following command:
$ cargo install cargo-dinghy
This crate is just a placeholder to be deployed on crates.io with the dinghy name, it fails on compilation to prompt users to install the correct crate.