Currently there is no way to automatically validate changes to docker-compose.yml or the images it uses upstream.
We should figure out some way to do implement tests for the configuration YAML and relevant dev images so we can catch regressions.
One idea would be to have a job in CI that looks to see if a patch is touching docker-compose.yml. If so the job could ping a tool on a Cloud-VPS instance, and that tool would pull the patch, run docker-compose up -d and generally run through the install steps and assert that a MediaWiki site instance is running correctly at the end.