Explain how to install Homebrew on Mac

[nbdani]

On Mac, the Homebrew package manager (brew command) used for installing jq and yq is not available by default.

You should explain how to install it, see here: https://brew.sh

[alwil]

as the intructions for installing yq / jq, where removed as per #18, i it s' not needed. Closing the issue.

[alwil]

I can see jq is still needed, i will reopen the issue and reintroduce the jq instructions