app manager (weblate): Update images:

Update image to run on latest version, pin PostgreSQL to v18, and remove the now
deprecated `version` field.

libervia/backend/plugins/plugin_app_manager_docker/libervia_app_weblate.yaml

@@ -6,9 +6,9 @@ files:
     content: |
       USE_X_FORWARDED_HOST = True
 override:
-  version: "3"
   services:
     weblate:
+      image: weblate/weblate:latest
       ports:
         - "8080"
       environment:
@@ -25,6 +25,10 @@ override:
         WEBLATE_ENABLE_HTTPS: !libervia_conf ["application.weblate", "enable_https", "1"]
       volumes:
         - ./settings-override.py:/app/data/settings-override.py:ro
+    database:
+      image: postgres:18-alpine
+    cache:
+      image: valkey/valkey:9.1.0
 expose:
   url_prefix: [override, services, weblate, environment, WEBLATE_URL_PREFIX]
   web_url_path: !libervia_param [front_url_path, /translate]