update to postgres 16.1 and remove unused Mock

Author: Daniel-Faber

docker-compose.yml

@@ -51,7 +51,7 @@ services:
       - "5005:80"
 
   postgres:
-    image: postgres:9.6
+    image: postgres:16.1
     environment:
       - POSTGRES_USER=allocation
       - POSTGRES_PASSWORD=abc123

tests/integration/test_uow.py

@@ -3,7 +3,6 @@
 import time
 import traceback
 from typing import List
-from unittest.mock import Mock
 import pytest
 from allocation.domain import model
 from allocation.service_layer import unit_of_work