doc: Update README.md about utf-8 validate (#10)

README.md

@@ -11,9 +11,10 @@
 
 A fast Rust JSON library based on SIMD. It has some references to other open-source libraries like [sonic_cpp](https://github.com/bytedance/sonic-cpp), [serde_json](https://github.com/serde-rs/json), [sonic](https://github.com/bytedance/sonic), [simdjson](https://github.com/simdjson/simdjson) and [rust-lang](https://github.com/rust-lang/rust).
 
-## Requirements
+## Requirements/Notes
 1. Support x86_64 or aarch64. Note that the performance in aarch64 is low and it need to optimize.
 2. Rust nightly version. Because we use the `packed_simd` crate.
+3. Not validating the UTF-8 in parsing. We will add a feature/option to enable it in the future.
 
 ## Features
 1. Serde into Rust struct as `serde_json` and `serde`