advertise content in the project pythia collection

[dcherian]

It would be good to add this repo to the list at https://projectpythia.org/resource-gallery.html

[cassienickles]

Submitted an issue to be added to the repo list: ProjectPythia/projectpythia.github.io#366

[cassienickles]

Currently there is a PR to pull in the cookbook into project pythia: ProjectPythia/projectpythia.github.io#385

[cassienickles]

Advertised! The team got the above PR through 🎉

[dcherian]

Nice work!