Update to use postgres:13

Avoids having to upgrade on centos stream updates. Only needs to change if/when
ovirt-engine requires postgres:14 or above.

Signed-off-by: geoff o'callaghan <geoffocallaghan@gmail.com>

docker-compose.yml

@@ -1,7 +1,7 @@
 
 services:
   ovirt-postgres:
-    image: postgres:13.16
+    image: postgres:13
     container_name: ovirt-postgres
     ports:
       - "5432:5432"