chore: upgrade to 3.1.0+2.4.0

compose.mariadb.yml

@@ -18,12 +18,16 @@ services:
       - db
 
   db:
-    image: mariadb:11.8
+    image: mariadb:12.3
     environment:
       - MYSQL_ROOT_PASSWORD_FILE=/run/secrets/db_root_password
       - MYSQL_PASSWORD_FILE=/run/secrets/db_password
       - MYSQL_USER=kuma
       - MYSQL_DATABASE=kuma
+      # Run mariadb-upgrade automatically when the data dir is from an older
+      # major version (e.g. 11.x -> 12.x). Needed because this overlay can be
+      # carried across MariaDB major bumps.
+      - MARIADB_AUTO_UPGRADE=1
     volumes:
       - mariadb:/var/lib/mysql
     networks: