Migrate to cargo_embargo. am: f13a18b8e7 am: f8bf439bbe am: 3e77a66d32

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/libloading/+/2838079

Change-Id: Ic08287612c186cc542a3601776c0ae919c77371c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>