Migrate to cargo_embargo. am: c2b6366a64 am: 8b9af7e561 am: c4b7b15547

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

Change-Id: I33748301107d010fb888e0585f7ca4f9380f3c02
Signed-off-by: Automerger Merge Worker <[email protected]>