adjust ups requirement

docs/get-started/system-requirements.md

@@ -13,7 +13,11 @@ The following are the minimum system requirements for running a full node, with
 - Storage: SSD with 2 TB free space
 - Operating system: 64-bit Linux, Mac OS X, or Windows
 - Internet: Broadband internet connection (10 Mbps)
-- Power: Uninterruptible power supply (UPS)
+
+:::note
+We also recommend that you have an uninterrupted power supply (UPS) to ensure your node is always available.
+However, this is not required.
+:::
 
 You can use [Prometheus](../how-to/monitor/use-metrics.md) to check CPU and disk space requirements for Teku.
 Grafana provides a [sample Teku dashboard](https://grafana.com/grafana/dashboards/13457).