... mostly to get CI.
Note that this adds the Cargo.lock file because we require pinning,
but it is generally not required for Rust libraries.
Change-Id: I565c7c8e899694accf3efd825ff46225f3c47d1a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3363
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI
