Create medium-sized demo repo

In addition to creating a tiny repo on the fly during the workshop and working only with that, also prepare a medium sized repo which has

• some files and folders
• a setup.py and the usual build metadata in case of Python
• a CI yaml file
• a README
• some issues with different labels

This can be used for exercises such as "suppose you are a new member in the project, let's filter out all issues witha "Bug" flag.