Tutorial doesn't work

I've forked this tutorial and attempted to deploy the Flask app via Github Actions, but I'm still seeing the default Microsoft app.
When SSH'ing into the machine, I can see that there's an archive with the contents of my repository under.
/home/site/wwwroot
The archive never ends up being decompressed, is that expected? Looking at the logs, decompression is never even attempted:

{
      "log_time":"2021-06-15T02:30:22.6898161Z",
      "id":"",
      "message":"Copied the compressed output to '/home/site/wwwroot'",
      "type":0,
      "details_url":null
   },
   [...]
   {
      "log_time":"2021-06-15T02:30:22.7293111Z",
      "id":"",
      "message":"Removing existing manifest file",
      "type":0,
      "details_url":null
   },
  [... nothing about un-taring ... ]