Migrate to cargo_embargo. am: e5d8474b88 am: 8207acb7d7 am: ae3dc001b9

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/cast/+/2822151

Change-Id: Ib70827285f03360f36d5efa85e54a13db9db32e5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>