Wrong usage of `include_bytes!` in README file of pb-rs

[JanBeh]

These lines seem to be wrong:

mod hello {
    include_bytes!(concat!(env!("OUT_DIR")), "/hello.rs");
}

It should be include! instead of include_bytes! and parentheses are wrong. Moreover, top-level attributes make inclusion impossible. See this post and follow-ups on URLO.