Migrate to cargo_embargo. am: 57f7c032aa am: 8193a2bb29 am: 82d5e36cc4

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/unicode-xid/+/2828135

Change-Id: I21c7bc29f49db2315f16b21b6d6ce0040d7ba1b2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>