Replace dev builds with stable release after JDK version is retired

[fniephaus]

Even though we've implemented is #31, dev builds will still break projects in case a specific JDK version is required for a project but not available anymore due to it being retired.
Instead of breaking these projects hard, we should probably fall back to the latest stable release for the specific JDK version and print a warning that the builds are no longer using a dev build.