docs built failed for unknown feature stdsimd

[Xuanwo]

error[E0635]: unknown feature `stdsimd`
  --> /home/runner/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ahash-0.7.7/src/lib.rs:33:42
   |
33 | #![cfg_attr(feature = "stdsimd", feature(stdsimd))]
   |                                          ^^^^^^^

For more information about this error, try `rustc --explain E0635`.

The latest nightly removed this feature.

We should

• Upgrade ahash to avoid this
• Pin current CI to old nightly

[Xuanwo]

Related to tkaitchuck/aHash#200

[Xuanwo]

ahash released a new version.