chore(tvix/store): trim Cargo.toml

lazy_static is only used in tests, and anyhow isn't used at all (yet).

This can be dropped.

Change-Id: Ic41ff3f9bb93cfa600c3485e85464f78a3976504
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7668
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

tvix/store/src/proto.rs

@@ -1,4 +1,3 @@
-use anyhow::Result;
 use std::collections::HashSet;
 use thiserror::Error;