[kimai] guide contains no longer working command

[Schoeneh]

The guide for kimai at https://lab.uberspace.de/guide_kimai/?highlight=kimai#finishing-installation contains the no longer working command kimai:create-user. According to the kimai documentation, it should be kimai:user:create: https://www.kimai.org/documentation/installation.html#create-your-first-user. I tested it yesterday, only by using the new command was I able to finish my setup.

I'm already working on a pull-request, but according to the contributing guidelines, I have to open an issue first.