Update postgres Docker tag to v18 (#63)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

docker/docker-compose.dev.yaml

@@ -1,6 +1,6 @@
 services:
   postgres:
-    image: "postgres:17.8"
+    image: "postgres:18.2"
     container_name: module-management-db
     environment:
       POSTGRES_DB: ${DB_NAME}

docker/docker-compose.prod.yaml

@@ -17,7 +17,7 @@ services:
     restart: unless-stopped
 
   postgres:
-    image: postgres:17.8
+    image: postgres:18.2
     container_name: module-management-db
     environment:
       - "POSTGRES_DB=${DB_NAME}"

docker/docker-compose.staging.yaml

@@ -18,7 +18,7 @@ services:
     restart: unless-stopped
 
   postgres:
-    image: postgres:17.8
+    image: postgres:18.2
     container_name: module-management-db
     environment:
       - "POSTGRES_DB=${DB_NAME}"