Migrate to cargo_embargo. am: f23ad98f7e am: 0be584b082 am: b1f1aab15f

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/pest_generator/+/2821939

Change-Id: I6dc1c911276a31c5065263dcd6d54dae4721003f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>