Migrate to cargo_embargo. am: b8374cfeae

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/idna/+/2822155

Change-Id: I10ff5dd49adfaff2cfcd800bc68e4a43839b49f7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>