Vendor dependencies

Let's see how I like this workflow.

vendor/pin-project-lite/tests/auxiliary/mod.rs

@@ -0,0 +1,12 @@
+#![allow(dead_code, unused_macros)]
+
+macro_rules! assert_unpin {
+    ($ty:ty) => {
+        static_assertions::assert_impl_all!($ty: Unpin);
+    };
+}
+macro_rules! assert_not_unpin {
+    ($ty:ty) => {
+        static_assertions::assert_not_impl_all!($ty: Unpin);
+    };
+}