Fix typo in README

PiperOrigin-RevId: 588301660

README.md

diff --git a/README.md b/README.md
index 75f64b3..6b32037 100644
--- a/README.md
+++ b/README.md
@@ -49,10 +49,10 @@
 ### Regression Test
 
 ```shell
-$ ui-automator --commission DEVICE_NAME,PAIRING_CODE,ROOM_NAME --reg-test [--repeat <REPEAT_TIMES>]
+$ ui-automator --commission DEVICE_NAME,PAIRING_CODE,ROOM_NAME --regtest [--repeat <REPEAT_TIMES>]
 ```
 
-*   flag `--reg-test` is required
+*   flag `--regtest` is required
 *   regression test need to be used with flag `--commission`
 *   regression test now only supports commissioning/decommissioning cycle
 *   defaultly, regression test will run until users use keyboard interrupt to