Upgrade rust/crates/async-trait to 0.1.48

Test: make
Change-Id: I898f35cd086b1bd9952eba11d5d59d31f78a5d16
diff --git a/src/lib.rs b/src/lib.rs
index 929af4f..100bee6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -303,7 +303,16 @@
 //! let object = &value as &dyn ObjectSafe;
 //! ```
 
-#![allow(clippy::match_like_matches_macro)] // matches! requires Rust 1.42
+#![allow(
+    clippy::default_trait_access,
+    clippy::doc_markdown,
+    clippy::if_not_else,
+    clippy::items_after_statements,
+    clippy::module_name_repetitions,
+    clippy::shadow_unrelated,
+    clippy::similar_names,
+    clippy::too_many_lines
+)]
 
 extern crate proc_macro;
 
@@ -312,7 +321,6 @@
 mod lifetime;
 mod parse;
 mod receiver;
-mod respan;
 
 use crate::args::Args;
 use crate::expand::expand;