Vendor dependencies

Let's see how I like this workflow.

vendor/getrandom/tests/normal.rs

@@ -0,0 +1,11 @@
+// Don't test on custom wasm32-unknown-unknown
+#![cfg(not(all(
+    target_arch = "wasm32",
+    target_os = "unknown",
+    feature = "custom",
+    not(feature = "js")
+)))]
+
+// Use the normal getrandom implementation on this architecture.
+use getrandom::getrandom as getrandom_impl;
+mod common;