No immediate build using github action after source repo changed

Describe the issue
We have a travis cron job that should run at least once a day (currently every 4 hours) to fetch, build and publish updated documentation.
Although documentation has been updated on the different repos, it re-publishes only the documentation already public.
Only if you push a change to the ods-documentation repository, the new version of the other repositories is correctly published.

Describe the expected behaviour
Whenever documentation has been updated in any of the repositories, the cron job should pick the changes up and correctly publish the changes.

Start by inspecting the Travis cron job and the build-and-publish workflow described in the issue, then reproduce a run after documentation changes in another repository. Done means the scheduled job detects and publishes those changes without requiring a push to ods-documentation.