Upgrade remain to 0.2.12 am: f4f0115e22

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/remain/+/2953097

Change-Id: I09f8730a2c022b36db0c1da5a28c29424d44e3d0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>