Add Trusty rules.mk file am: 7513c72639

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-trait/+/2770391

Change-Id: Id26f445e6af8047cc6096be54bb3f9a811960297
Signed-off-by: Automerger Merge Worker <[email protected]>