Use docker compose plugin

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

handlers/main.yml

@@ -4,6 +4,6 @@
     cmd: "{{ item }}"
     chdir: "{{ mailcow_folder }}/"
   loop:
-    - docker-compose down
-    - docker-compose up -d
+    - docker compose down
+    - docker compose up -d
   when: not mailcow_start.changed