Migrate to cargo_embargo. am: b6e9f2e4a4 am: 76a56ea196 am: 25308a37f4

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/regex-syntax/+/2821942

Change-Id: I6e6dff85f9eb3d5ba8f93ac434d513cd0c8b94a7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>