nightly features packed sims feature not available

[jianshu93]

Hello @alecmocatta,

Since the nightly Rust v1.78, feature stdsimd does not exists any more:
error[E0557]: feature has been removed
--> /Users/jianshuzhao/.cargo/registry/src/index.crates.io-6f17d22bba15001f/packed_simd-0.3.9/src/lib.rs:218:5
|
218 | platform_intrinsics,
| ^^^^^^^^^^^^^^^^^^^ feature has been removed
|
= note: SIMD intrinsics use the regular intrinsics ABI now

We need some updates.

Thanks,

Jianshu