Hmm. Make sure you copied the Raw version of the gist. https://gist.githubusercontent.com/bennewton999/4a1ca803d9345c3618c0c3b30cf96aa8/raw/1a084d1245abc7d7bed66a26e50b3a58331957d1/task.md

and make sure you have the dataview plugin installed as well. Cmd-e to preview.