What I am ultmately trying to do is when one of the upstream images for my dockerfiles (e.g. Ubuntu image on Dockerhub) has been updated, I want to run all of the relevant Docker builds so that they will automatically be updated in production with the latest image fixes.
I suspect this is not easy or possible so then I had another thought for a way this could be achieved. Is it possible to set a trigger that runs e.g. once per month (when MS releases its Docker updates) but only run it if it hasn't already built in the last month?
It wouldn't be the end of the world but I'm not sure I would want to run a build from a code change and then run all of the builds again a day later when an update appears, would rather wait until another month has passed.
Otherwise, it looks like my only option is a simple schedule trigger. Is that correct?