constant `MAX_SHARD_SIZE` is never used

function `shard_size` is never used

could not compile `sp1-stark` (lib test) due to 2 previous errors

The process '/home/runner/.cargo/bin/cargo' failed with exit code 101

This job failure may be caused by using an out of date self-hosted runner. You are currently using runner version 2.319.1. Please update to the latest version 2.320.0

The following actions uses node12 which is deprecated and will be forced to run on node16: actions-rs/cargo@v1. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/