Migrate to cargo_embargo. am: 97e013e49b am: 63eb4811b7 am: d7e7d52733

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-task/+/2796115

Change-Id: I8efc3b2953632f3ae64204227e08cfae9a5656ad
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>