Consider publishing an update to crates.io

[SSheldon]

The latest version of this crate on crates.io, 0.0.0, was published on March 21st. A lot has changed since then!

In particular, that version still used version 0.1 of the objc crate, which will fail to compile after rust-lang/rust#34198. metl has since been updated to use version 0.2 in a82dd50.

Rust uses a tool called crater that will build the latest version of each crate and verify it hasn't regressed; if you publish a new version, it'll keep passing on crater and the rust devs can verify going forward that they haven't broken any functionality you rely on.