Fix registry tags.

Instead of making the matrix more complicated, ensure that all my images have a `latest` tag.

Author: rpgoldman

.github/workflows/ci.yml

@@ -55,9 +55,6 @@ jobs:
           - l: abcl
             IMAGE_TAG: 1.7.1-jdk8 # FIXME: this is likely obsolete
             PREFIX: containers.common-lisp.net/cl-docker-images
-          - l: abcl
-            IMAGE_TAG: 1.9.0
-            PREFIX: docker.io/rpgoldman
     env:
       GITHUB_ACTION: true
       I_AGREE_TO_ALLEGRO_EXPRESS_LICENSE: yes