1.8.4

version 1.8.4

Changes since 1.8.3:

• Updated the digest dependency from v0.10 to v0.11. THIS IS A
  POTENTIALLY BREAKING CHANGE for callers using the traits-preview
  Cargo feature. But this is not considered a breaking change for the
  blake3 crate itself; see the docs for traits-preview.
• Performance for WASM SIMD targets is improved by ~20% when the
  wasm32_simd feature is enabled. Contributed by @lamb356.