Update old references to com.devture.ansible.role.postgres & com.devture.ansible.role.traefik

Provoked by https://github.com/mother-of-all-self-hosting/mash-playbook/pull/280

roles/custom/matrix-bridge-appservice-slack/tasks/migrate_nedb_to_postgres.yml

@@ -2,7 +2,7 @@
 
 - name: Fail if Postgres not enabled
   ansible.builtin.fail:
-    msg: "Postgres via the com.devture.ansible.role.postgres role is not enabled (`postgres_enabled`). Cannot migrate."
+    msg: "Postgres via ansible-role-postgres role is not enabled (`postgres_enabled`). Cannot migrate."
   when: "not postgres_enabled | bool"
 
 # Defaults