Screenshots for main steps

[arockenberger]

I would like to take a couple of screenshots for the main steps of the lesson, especially setup, pull request, issues, and navigating the settings .

[arockenberger]

GitHub changes how the sign up looks ever so often, it makes no sense to take screenshots for this.

For pull requests and issues: possibly useful.

Repo settings seem to change once in a while, too, but might be useful.

Alternatively: make a video for these steps?