Migrate to cargo_embargo. am: 3742ab94f0 am: eab417ce75 am: 97e9f86399

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/which/+/2822243

Change-Id: I76a5645cd22056cf09fac1c2162dcda8d4d9f74d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>