Migrate to cargo_embargo. am: f78d645463 am: b6a0dfcdb9 am: ad2ad7b879

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

Change-Id: Ia39291a26493c3164eea16d9318d7e3404563cb7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>