Cargo update without rust_eth_kzg (#6848)

Update cargo dependencies while keeping `rust_eth_kzg` pinned to `0.5.1` due to the regression described in:

- #6608

The changes from that PR were not sufficient to actually pin the dependencies of `rust_eth_kzg`, because the dependencies from the workspace Cargo.toml file were not being used anywhere. To fix this, I've added them as explicit dependencies in `crypto/kzg/Cargo.toml`. With this change, `cargo update` no longer tries to update them.

Author: michaelsproul