Hmm, I don’t entirely understand why I, as a user, need to take action on this. I would understand if I had selected a specific version of Ruby or another dependency, but I never did. As I understand it, a default was assigned when I created the build, and that default is just no longer valid.
What seems proper to me is that I should now get a different default. Sure, people who have specifically selected a different dependency version will need to take action, but those people probably already know that they pinned the dependency version.
In my case, I’d be perfectly happy to have all my defaults blown away and recreated with the latest defaults, that will actually work. Even telling me that you’ll automatically upgrade the versions would be confusing, because I’m not aware of anything like this (“I just used the image and installed my Python package on it, why am I getting a message about Go?”).