Upgrade rust/crates/async-trait to 0.1.48

Test: make
Change-Id: I898f35cd086b1bd9952eba11d5d59d31f78a5d16
diff --git a/tests/ui/send-not-implemented.stderr b/tests/ui/send-not-implemented.stderr
index 05c445b..473a31b 100644
--- a/tests/ui/send-not-implemented.stderr
+++ b/tests/ui/send-not-implemented.stderr
@@ -7,7 +7,7 @@
 10 | |         let _guard = mutex.lock().unwrap();
 11 | |         f().await;
 12 | |     }
-   | |_____^ future returned by `__test` is not `Send`
+   | |_____^ future created by async block is not `Send`
    |
    = help: within `impl Future`, the trait `Send` is not implemented for `MutexGuard<'_, ()>`
 note: future is not `Send` as this value is used across an await
@@ -20,3 +20,28 @@
 12 |     }
    |     - `_guard` is later dropped here
    = note: required for the cast to the object type `dyn Future<Output = ()> + Send`
+
+error: future cannot be sent between threads safely
+  --> $DIR/send-not-implemented.rs:14:38
+   |
+14 |       async fn test_ret(&self) -> bool {
+   |  ______________________________________^
+15 | |         let mutex = Mutex::new(());
+16 | |         let _guard = mutex.lock().unwrap();
+17 | |         f().await;
+18 | |         true
+19 | |     }
+   | |_____^ future created by async block is not `Send`
+   |
+   = help: within `impl Future`, the trait `Send` is not implemented for `MutexGuard<'_, ()>`
+note: future is not `Send` as this value is used across an await
+  --> $DIR/send-not-implemented.rs:17:9
+   |
+16 |         let _guard = mutex.lock().unwrap();
+   |             ------ has type `MutexGuard<'_, ()>` which is not `Send`
+17 |         f().await;
+   |         ^^^^^^^^^ await occurs here, with `_guard` maybe used later
+18 |         true
+19 |     }
+   |     - `_guard` is later dropped here
+   = note: required for the cast to the object type `dyn Future<Output = bool> + Send`