Migrate to cargo_embargo. am: 8725301739 am: 2b1166aff1

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/shared_child/+/2838082

Change-Id: Iac57f648d5a4e053b5443ba27aecf8e7b8eac955
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>