this?

.woodpecker/.base-os.yml

@@ -1,7 +1,7 @@
-#matrix:
-  #  DEBIAN_VERSION:
-    #    - bullseye-backports
-      #    - bookworm-backports
+matrix:
+  DEBIAN_VERSION:
+    - bullseye-backports
+    - bookworm-backports
 
 steps:
   build-os:
@@ -11,9 +11,12 @@ steps:
       repo: gitea.simcop2387.info/simcop2387/perl-os-base
       dockerfile: os-base/Dockerfile 
       context: os-base/
+      auto_tag: false
+      default_tag: debian-${DEBIAN_VERSION}
       build_args:
-        IMAGE_VERSION: bookworm-backports
-      tag: debian-bookworm-${CI_PIPELINE_CREATED}
+        - IMAGE_VERSION=$DEBIAN_VERSION
+      tags:
+        - debian-${DEBIAN_VERSION}-${CI_PIPELINE_CREATED}
       logins:
         - registry: https://gitea.simcop2387.info/
           username: simcop2387