groupware: fix GROUPWARE_JMAP_MASTER_USERNAME to Stalwart 0.16 requirements for using the primary email instead of the username

devtools/deployments/opencloud_full/opencloud.yml

@@ -67,7 +67,7 @@ services:
       IDM_LDAPS_KEY: /etc/opencloud/certs/ldaps.key
       OC_LDAP_CACERT: /etc/opencloud/certs/ldaps.crt
       GROUPWARE_JMAP_BASE_URL: https://${STALWART_DOMAIN:-stalwart.opencloud.test}
-      GROUPWARE_JMAP_MASTER_USERNAME: "master"
+      GROUPWARE_JMAP_MASTER_USERNAME: "admin@example.org"
       GROUPWARE_JMAP_MASTER_PASSWORD: "admin"
     volumes:
       - ./config/opencloud/app-registry.yaml:/etc/opencloud/app-registry.yaml