Migrate to cargo_embargo. am: 6183a6076e

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/fastrand/+/2822398

Change-Id: Icda363e6ca93c9c6f565d58e498b337310a022f4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>