update to compliant yaml anchor usage

compose.yml

@@ -10,8 +10,7 @@ x-redis-env: &redis-env
   REDIS_URL: redis://redis:6379
 
 x-environment: &default-env
-  <<: *db-env
-  <<: *redis-env
+  <<: [*db-env, *redis-env]
   CANONICAL_HOST: ${DOMAIN}
   VIRTUAL_HOST: ${DOMAIN}
   CHANNELS_URI: wss://channels.${DOMAIN}
@@ -71,7 +70,7 @@ services:
         - "traefik.http.routers.${STACK_NAME}.rule=Host(`${DOMAIN}`${EXTRA_DOMAINS})"
         - "traefik.http.routers.${STACK_NAME}.entrypoints=web-secure"
         - "traefik.http.routers.${STACK_NAME}.tls.certresolver=${LETS_ENCRYPT_ENV}"
-        - "coop-cloud.${STACK_NAME}.version=3.0.0+v2.25.3"
+        - "coop-cloud.${STACK_NAME}.version=4.0.0+v2.25.3"
         - "backupbot.backup:=${ENABLE_BACKUPS:-true}"
   worker:
     image: loomio/loomio:v2.25.3
@@ -98,7 +97,7 @@ services:
       - loomio_plugins:/loomio/plugins/docker
   db:
     # loomio version upgrades and postgres version upgrade should not be performed at the same time.
-    image: postgres:12.17
+    image: pgautoupgrade/pgautoupgrade:17-debian
     networks:
       - backend
     volumes:

release/4.0.0+v2.25.3

@@ -0,0 +1 @@
+ATTENTION: Perform a deployment of version 3.0.0+v2.25.3 before upgrading to this version. Otherwise there will be complications with database migrations. This version upgrades the used postgres container to version 17 with auto-upgrade functionality.