Vendor dependencies

Let's see how I like this workflow.

vendor/wasm-bindgen/tests/must_use.rs

@@ -0,0 +1,10 @@
+//! This test validates that the generated bindings don't cause linting warnings
+//! when used with structs annotated with `#[must_use]`.
+
+#![deny(unused)]
+
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+#[must_use]
+pub struct MustUse {}