It doesn’t look like you followed step #2 here like it said since your requirements.txt file lacks voila.
Also the URL on your badge didn’t seem to be correct. You need follow the example on the launch binder badge in the voila README.
If you go here and launch you’ll see voila tries to run it, but seems to intermittently have an issue with data fetching. (I found it worked on a try later when I ran it in the Jupyter notebook interface first before switching back to the Voila session URL. I doubt that made much difference honestly.) I added the basics one from the voila example and that one works reliably well when you select it from the list.