Replace cargo-cranky with workspace lints (#4413)

Replace `cargo-cranky` (which has served us well) with workspace lints

crates/egui_demo_app/src/apps/custom3d_glow.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::undocumented_unsafe_blocks)]
+
 use std::sync::Arc;
 
 use eframe::egui_glow;