postgresql upgrade(11.5 -> 11.6)

Signed-off-by: tunagohan <kazuxtuna@gmail.com>

Author: tunagohan

deployments/docker-compose.yml

@@ -1,7 +1,7 @@
 version: "3"
 services:
   database:
-    image: postgres:11.5
+    image: postgres:11.6-alpine
     environment:
       - POSTGRES_USER=codimd
       - POSTGRES_PASSWORD=change_password