Adjust download script to work with githubs new API

[borgmanJeremy]

The current wget command in the README does not work anymore. Github changed their website so the actual release info is no longer embedded into the html and is dynamically loaded.

To properly fetch the latest releasing info they recommend using their API as described here: https://docs.github.com/en/rest/releases/releases#list-releases

This changes the README to use the new API and filter with jq (since its parsing JSON).