[skip e2e]Update README for chaos test (#14546)

Signed-off-by: Nzhuwenxing <wenxing.zhu@zilliz.com>

tests/python_client/chaos/README.md

@@ -74,9 +74,9 @@ Run test scenario automatically:
 2. run the commands below:
    ```bash
    cd /milvus/tests/python_client/chaos
-   # in this step, script will install milvus and run testcase
-   bash chaos_test.sh ${pod} ${chaos_type} ${chaos_task}
-   # example: bash chaos_test.sh querynode pod_kill chaos-test
+   # in this step, script will install milvus with replicas_num and run testcase
+   bash chaos_test.sh ${pod} ${chaos_type} ${chaos_task} ${replicas_num}
+   # example: bash chaos_test.sh querynode pod_kill chaos-test 2
    ```
 ### Github Action
 * [Pod Kill Chaos Test](https://github.com/milvus-io/milvus/actions/workflows/pod-kill-chaos-test.yaml)