## Proposed Changes
Modify the SHA256 implementation in `eth2_hashing` so that it switches between `ring` and `sha2` to take advantage of [x86_64 SHA extensions](https://en.wikipedia.org/wiki/Intel_SHA_extensions). The extensions are available on modern Intel and AMD CPUs, and seem to provide a considerable speed-up: on my Ryzen 5950X it dropped state tree hashing times by about 30% from 35ms to 25ms (on Prater).
## Additional Info
The extensions became available in the `sha2` crate [last year](https://www.reddit.com/r/rust/comments/hf2vcx/ann_rustcryptos_sha1_and_sha2_now_support/), and are not available in Ring, which uses a [pure Rust implementation of sha2](https://github.com/briansmith/ring/blob/main/src/digest/sha2.rs). Ring is faster on CPUs that lack the extensions so I've implemented a runtime switch to use `sha2` only when the extensions are available. The runtime switching seems to impose a miniscule penalty (see the benchmarks linked below).
## Issue Addressed
- Resolves#1706
## Proposed Changes
Updates dependencies across the workspace. Any crate that was not able to be brought to the latest version is listed in #1712.
## Additional Info
NA
## Issue Addressed
NA
## Proposed Changes
Adds support for using the [`cross`](https://github.com/rust-embedded/cross) project to produce cross-compiled binaries using Docker images.
Provides quite clean and simple cross-compiles cause all the complexity is hidden in Dockerfiles. It does require you to be in the `docker` group though.
## Details
- Adds shortcut commands to `Makefile`
- Ensures `reqwest` and `discv5` use vendored openssl libs (i.e., static not shared).
- Switches to a [commit](284f705964) of blst that has a renamed C function to avoid a collision with openssl (upstream issue: https://github.com/supranational/blst/issues/21).
- Updates `ring` to the latest satisfiable version, since an earlier version was causing issues with `cross`.
- Off-topic, but adds extra message about Windows support as suggested by Discord user.
## Additional Info
- ~~Blocked on #1495~~
- There are no tests in CI for this yet for a few reasons:
- I'm hesitant to add more long-running tasks.
- Short-term bitrot should be avoided since we'll use it each release.
- In the long term I think it would be good to automate binary creation on a release.
- I observed the binaries increase in size from 50mb to 52mb after these changes.
