Upgrade rust/crates/protobuf-codegen to 2.18.1 am: b62512d3c6 am: 57694ec33f

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/protobuf-codegen/+/1510356

Change-Id: I2abeb0fc28b199f2ca8d678cd5641918567926fe