message: added sign-off
diff: # Setup Indy SDK build environment for MacOS
  1. Install Rust and rustup (https://www.rust-lang.org/install.html).
  -2. Install required native libraries and utilities (libsodium is added with URL since non-latest version is required for it to function)
  +2. Install required native libraries and utilities (libsodium is added with URL to homebrew since version<1.0.15 is required)
  ```
  brew install pkg-config
  