Disable AVX2 in macOS ARM wheels (#483)

As AVX2 is an `x86_64` feature, ARM understandably doesn't have it.
However for some reason macOS ARM wheels are building with this
functionality enabled. So disable it in `pyproject.toml`. Hopefully this
should fix that issue.

Author: jakirkham

pyproject.toml

@@ -118,4 +118,4 @@ environment = { DISABLE_NUMCODECS_AVX2=1 }
 environment = { MACOSX_DEPLOYMENT_TARGET=10.9, DISABLE_NUMCODECS_AVX2=1, CFLAGS="$CFLAGS -Wno-implicit-function-declaration" }
 [[tool.cibuildwheel.overrides]]
 select = "*-macosx_arm64"
-environment = { DISABLE_NUMCODECS_SSE2=1 } 
+environment = { DISABLE_NUMCODECS_AVX2=1, DISABLE_NUMCODECS_SSE2=1 }