Add wasm32 to the list of target architectures of the simd feature

[roee88]

packed_simd compiles to wasm32-wasi and wasm32-unknown-unknown targets (and includes CI against it). It will only work on WASM runtimes that support the WASM SIMD proposal but that's no reason to block it from arrow-rs side.

Describe the solution you'd like

Add wasm32 to

arrow-rs/arrow/build.rs

Line 24 in c863a2c

simd: { all(any(target_arch = "x86", target_arch = "x86_64", target_arch = "aarch64"), feature = "simd") },

Describe alternatives you've considered

Optional features should not be limited to specific architectures in arrow-rs itself. The arrow-rs CI shouldn't run tests with combinations that are not known to work, but as a user I would expect that if I enable a feature then it's enabled (and might create a failure on its own if it doesn't work yet). It took me a while to understand why I get the error described in #232 when targeting wasm32. This would probably require changes to the CI workflows though.