Migrate to cargo_embargo. am: 57a5148ddd am: f625e02646

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/indexmap/+/2832458

Change-Id: I53ebe68ae47cc197a50c644a899b5449ef990ffd
Signed-off-by: Automerger Merge Worker <[email protected]>