Retiring community UBI 8 images for Quarkus

As you may know, Quarkus provides container images based on Red Hat Universal Base Image (UBI) both for building applications and for running them. Since Quarkus 3.19, Quarkus is using UBI 9 as the default base image for container images. Given the oldest version we maintain in the community is 3.20 LTS, we have decided to retire the community UBI 8 images for Quarkus in March 2026.