✨(dimail) add dimail as a container dependency

Start the Dimail container (in CI and local testing) when starting
the app. The pull_policy should have no effect on CI (because it starts
from a blank slate) but ensure we test against the most recent version
of the chosen tag.

docker-compose.yml

@@ -35,6 +35,7 @@ services:
       - ./data/media:/data/media
       - ./data/static:/data/static
     depends_on:
+        - dimail
         - postgresql
         - mailcatcher
         - redis
@@ -168,7 +169,9 @@ services:
       - kc_postgresql
 
   dimail: 
+    entrypoint: /opt/dimail-api/start-dev.sh
     image: registry.mim-libre.fr/dimail/dimail-api:latest
+    pull_policy: always
     environment:
       DIMAIL_MODE: FAKE
       DIMAIL_JWT_SECRET: fake_jwt_secret