Migrate to cargo_embargo. am: efa01a6dd4 am: a4d95aa006 am: 5eb294985f

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/cfg-if/+/2822540

Change-Id: I547bfede5cb6100f9984ea3418b8476d11cc8e9f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>