Nightly feature stdsimd has been removed

[jayvdb]

The commit removing stdsimd is rust-lang/rust@ea37e80

Relevant tracking issues? rust-lang/rust#27731 and rust-lang/rust#48556

[BrettForr]

Hi, sorry I'm new to the space so don't know conventions etc. What's the path to resolving this? Is it work to do in this crate or something that needs to be done with nightly rust? I tried switching to an earlier version of nightly rust but that caused some other things to break for me, so wondering if I should keep going down that path or wait for a soon-coming fix.