Migrate to cargo_embargo. am: f41a4d0d53 am: 34d3546c25 am: 10a7f87fa5

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/protobuf-codegen/+/2862566

Change-Id: I55862126a19cb28e07f935fcfb595cc5d545fd98
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>