Remove objc workaround

Author: prokopyl

src/lib.rs

@@ -1,7 +1,3 @@
-// This is required because the objc crate is causing a lot of warnings: https://github.com/SSheldon/rust-objc/issues/125
-// Eventually we should migrate to the objc2 crate and remove this.
-#![allow(unexpected_cfgs)]
-
 #[cfg(target_os = "macos")]
 mod macos;
 #[cfg(target_os = "windows")]