chg: [rocketchat] update to version ``3.18.1``

Signed-off-by: Valentin Lab <valentin.lab@kalysto.org>

rocketchat/metadata.yml

@@ -1,7 +1,7 @@
 summary: "Rocket Chat server"
 maintainer: "Valentin Lab <valentin.lab@kalysto.org>"
-#docker-image: rocketchat/rocket.chat:3.14.0
-docker-image: docker.0k.io/rocketchat:3.14.0
+#docker-image: rocketchat/rocket.chat:3.18.1
+docker-image: docker.0k.io/rocketchat:3.18.1
 data-resources:
   - /app/uploads
 uses: