Migrate to cargo_embargo. am: c2b6366a64 am: 8b9af7e561

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/bstr/+/2794737

Change-Id: I3a43451f99c6e727385056003c5e723f233d0b52
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>