Should there be a dedicated item for major releases about [filing a task about] creating a Docker image, like https://phabricator.wikimedia.org/T213529 ?
If we do it, we should do it correct from the beginning and automate it, which would mean some subtask of https://phabricator.wikimedia.org/T156445
I think it should be up to the maintainers of the Docker image to keep on top of it (and they already do).
For automating docker specifically, we discussed it on https://github.com/wikimedia/mediawiki-docker/pull/36 but never finished the implementation.
And Debian has its own system of detecting new upstream releases: https://qa.debian.org/cgi-bin/watch?pkg=mediawiki