message: Fix macos install target path
diff: @@ -168,7 +168,7 @@ fn prebuilt_url(tool: &Tool, version: &str) -> Result<String, failure::Error> {
  _ => "x86_64-unknown-linux-musl",
  }
  } else if target::MACOS && (target::x86_64 || target::aarch64) {
  - "x86_64-apple-darwin"
  + "x86_64-macos"
  } else if target::WINDOWS && target::x86_64 {
  match tool {
  Tool::WasmOpt => "x86-windows",
  