Make tags publish draft releases

[sharkwouter]

This can be achieved using Github actions. The most important things to add are:

• [ ] Update version.py before building with the tag name
• [ ] Only trigger for tags which match a version number (like 1.21.4 for example, numbers only)
• [ ] Build a debian package (can be done with dpkg-buildpackage -us -uc)

Not sure how to deal with the debian changelog, for now assume it has already been updated.