Migrate to cargo_embargo. am: ff267a7f5f

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/regex/+/2824496

Change-Id: Icb32d559d8ba43cddbaf967c561438605d6902c2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>