Migrate to cargo_embargo. am: c82ca0ec5e

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/octets/+/2824490

Change-Id: Icb0c92bb492430a92242f27533352452de03fbc6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>