Migrate to cargo_embargo. am: f78d645463 am: 8213bb4ca5 am: d8cee6e61a

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/grpcio-compiler/+/2832422

Change-Id: I35b8164c149e9fea6488ca7f009e6d69522a7a6a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>