Docker-compose: upgrade to postgres 13

We have been using postgres 13 in production for a long time, but we never actually updated the docker-compose environment.

Author: Akarys42

docker-compose.yml

@@ -11,7 +11,7 @@
 version: "3.6"
 services:
   postgres:
-    image: postgres:12-alpine
+    image: postgres:13-alpine
     ports:
       - "127.0.0.1:7777:5432"
     environment: