Include some additional Git/GitHub references in the template

[scottyhq]

Over the last years there is always a fair amount of debate on how much time to spend discussing git & github, but it really is a central piece of hackweeks (getting tutorials into a jupyterbook website, and sharing code for projects). At our most recent event and others, there is usually significant interest in ad-hoc git tutorials!

Perhaps we add a bit more material to the 'what to expect page':
https://book-template.hackweek.io/preliminary/index.html#prerequisites

Could link to this great resource :)
https://github.com/uwhackweek/learning-git

And there are problably some new resources worth adding too like these official beginner guides
https://github.blog/tag/github-for-beginners/

cc @jomey

[jomey]

There is indeed a continued interest for ad-hoc tutorials during the event. Seems like we can not get away without having at least a basic intro