Split Docker image rebuilding and calendar rebuilding?
Assuming that building the docker image is required less frequently than rebuilding the calendar, please consider splitting the current CI step into two. Feel free to draw some inspiration from the Latex template CI workflow, where we also build the docker image in a separate step (https://gitlab.hrz.tu-chemnitz.de/scads.ai/latex-template/-/blob/main/.gitlab-ci.yml#L12).