Migrate to cargo_embargo. am: 99d47778c2

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/unicode-width/+/2828074

Change-Id: I11b75e982b7724010bdaeadcceacafb04103045f
Signed-off-by: Automerger Merge Worker <[email protected]>