The build takes too long
Looking at the last few pipelines (see https://gitlab.fel.cvut.cz/osy/osy.pages.fel.cvut.cz/pipelines), the elapsed time is around 6+ minutes. It's a lot for static pages generator.
The problem is that in each step, go language is compiled from source and Hugo is installed from the source afterward.
The solution is to create and/or (if exists) use the Hugo docker image.