Upgrade rust/crates/async-trait to 0.1.38

Change-Id: I894c990c19b1ac3d74e4bf002cf581b9875e730e
diff --git a/src/expand.rs b/src/expand.rs
index 7d0cec2..7c3ab5a 100644
--- a/src/expand.rs
+++ b/src/expand.rs
@@ -446,9 +446,11 @@
     let box_pin = quote_spanned!(brace.span=> {
         #[allow(
             #allow_non_snake_case
+            unused_parens, // https://github.com/dtolnay/async-trait/issues/118
             clippy::missing_docs_in_private_items,
             clippy::needless_lifetimes,
             clippy::ptr_arg,
+            clippy::trivially_copy_pass_by_ref,
             clippy::type_repetition_in_bounds,
             clippy::used_underscore_binding,
         )]