message: Update mac-build.md
  updated to include installation of latest libsodium.  This project no longer requires using an older version.
diff: @@ -8,7 +8,7 @@ Automated build: clone the repo and run `mac.build.sh` in the `libindy` folder.
  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
  - brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/65effd2b617bade68a8a2c5b39e1c3089cc0e945/Formula/libsodium.rb
  + brew install libsodium
  brew install automake
  brew install autoconf
  brew install cmake
  