Update services' versions

* specify last known working versions in the compose file
* previously the `latest` tag was not pulling the actual latest image since the build was local

docker-compose.yml

@@ -8,7 +8,7 @@ volumes:
 
 services:
   postgres:
-      image: postgres
+      image: postgres:13
       restart: always
       ports:
         - "5432:5432"
@@ -25,7 +25,7 @@ services:
           tag: "keycloak_db"
 
   keycloak:
-      image: quay.io/keycloak/keycloak:latest
+      image: quay.io/keycloak/keycloak:16.1.1
       restart: always
       environment:
         PROXY_ADDRESS_FORWARDING: "true"