Change docker-compose YAML files to use PostgreSQL version 12 image for "postgre…

…s" and "hybrid" types of database setup

@@ -19,7 +19,7 @@ version: '2.2'
 services:
 services:
   postgres:
   postgres:
     restart: always
     restart: always
-    image: "postgres:11.6"
+    image: "postgres:12"
     ports:
     ports:
       - "5432"
       - "5432"
     environment:
     environment:

@@ -19,7 +19,7 @@ version: '2.2'
 services:
 services:
   postgres:
   postgres:
     restart: always
     restart: always
-    image: "postgres:11.6"
+    image: "postgres:12"
     ports:
     ports:
     - "5432"
     - "5432"
     environment:
     environment: