... 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: Iedbd3758e8df8a7f60fe67b6b06c8e41aba8f345
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3362
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI