Upgrade Matomo

When there is a new Matomo release, we have to deploy it on our infrastructure (this is inspired from https://matomo.org/faq/on-premise/update-matomo/#the-manual-three-step-update and adapted to k8s and our setup):

• check the changelog and act accordingly
• check that Docker image for new version is available on Docker Hub
• update Matomo version in kiwix/container-images (update the Dockerfile AND the github CI default tag on main branch)
• let matomo image build
  • matomo-log-analytics image will also be rebuild automatically, but this is deployed automatically since it is a cronjob using latest image
• deploy the new image by modifying versions in kiwix/k8s
• open Matomo web UI
• click the "update available" button (only available if you are signed-in)
• trigger new version deployment (DB changes):
  • the UI might indicate that it is a large change and that is should be done via CLI on large installations ; we are a large installations ; do it via CLI when suggested
  • or if change is small, simply click the "update automatically" button
• restart the UI container and confirm everything is OK