The `gtk` crate is unmaintained

[samvv]

Cargo.toml depends on gtk but the crate is unmaintained. This is the message on crates.io:

UNMAINTAINED Rust bindings for the GTK+ 3 library (use gtk4 instead)

Ignoring this and compiling a GTK4 app anyways gives strange errors similar to this issue.

[samvv]

Just saw #201 which is related to this.