I suspect it means you need to pin your container image versions to at least a proven major version so that they don’t blindly upgrade out from under you. 
You do that using tags on your image references (don’t downgrade however unless you have a data migration strategy!):
https://hub.docker.com/_/postgres
I would do that going forward, but now you have to address where you’re at…
I suspect your db image bumped up from whatever you had before to a major new version.
From the looks of it you can resolve that issue by following it’s advice (roughly speaking):