[skip ci] Refine binary deployments doc (#11011)

Signed-off-by: NEdward Zeng <jie.zeng@zilliz.com>

deployments/binary/README.md

@@ -30,7 +30,7 @@ $ ./minio server /minio
 To start Milvus service, you need a Milvus binary file. Currently you can get the latest version of Milvus binary file through the Milvus docker image. (We will upload Milvus binary files in the future)
 
 ```shell
-$ docker run -d --name milvus milvusdb/milvus:v2.0.0-rc7-20211011-d567b21 /bin/bash
+$ docker run -d --name milvus milvusdb/milvus:v2.0.0-rc8-20211030-54738d2 /bin/bash
 $ docker cp milvus:/milvus .
 ```