Migrate to cargo_embargo. am: 2d80cc1212 am: b17690c332 am: e7c641191c

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/memchr/+/2828199

Change-Id: Iea40941a6eeeb6bcfe06f2a1ec2568f3efd159d5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>