chore(Postgres): Upgrade to 13.4 and 12.8

https://www.postgresql.org/docs/release/12.8/
https://www.postgresql.org/docs/release/13.4/

nextcloud/docker-compose.yml

@@ -59,7 +59,7 @@ services:
 
   nextcloud-postgres:
     container_name: ${POSTGRES_CONTAINER_NAME}
-    image: ${POSTGRES_IMAGE:-postgres:12.7-alpine}
+    image: ${POSTGRES_IMAGE:-postgres:12.8-alpine}
     restart: always
     environment:
       POSTGRES_USER: ${POSTGRES_USER}

postgres/docker-compose.yml

@@ -7,7 +7,7 @@ volumes:
 services:
   postgres:
     container_name: ${POSTGRES_CONTAINER_NAME:-postgres}
-    image: ${POSTGRES_IMAGE:-postgres:13.3-alpine}
+    image: ${POSTGRES_IMAGE:-postgres:13.4-alpine}
     restart: always
     environment:
       POSTGRES_USER: ${POSTGRES_USER:?err}