Replace cargo machete with cargo shear (#8094)

We've had good experiences with `cargo shear` at Rerun

tests/egui_tests/Cargo.toml

@@ -5,6 +5,9 @@ license.workspace = true
 rust-version.workspace = true
 version.workspace = true
 
+[package.metadata.cargo-shear]
+ignored = ["image"] # We need the png feature
+
 [dev-dependencies]
 egui = { workspace = true, default-features = true }
 egui_kittest = { workspace = true, features = ["snapshot", "wgpu"] }

tests/test_egui_extras_compilation/Cargo.toml

@@ -9,7 +9,7 @@ publish = false
 [lints]
 workspace = true
 
-[package.metadata.cargo-machete]
+[package.metadata.cargo-shear]
 ignored = ["eframe", "egui_extras"] # We don't use them, just check that things compile
 
 [dependencies]