Add metadata files for serde_cbor. am: f31352780d am: 71ef2e806c am: e7a73ad6b2 am: c49fd4eaaa

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/serde_cbor/+/1610054

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I8cef235900cc99d8daf73539356a4bdb0892177f