chore: sync template versions with image updates

library/compose/grafana/template.yaml

@@ -18,9 +18,9 @@ metadata:
     Username: admin
     Password: admin
     ```
-  version: 12.1.1
+  version: 12.3.1
   author: Christian Lempa
-  date: '2025-09-28'
+  date: '2025-12-16'
   tags:
     - traefik
     - authentik