[skip ci] Add comment of func parse_server_tag on benchmark (#7804)

Signed-off-by: Nwangting0128 <ting.wang@zilliz.com>

tests-deprecating/milvus_benchmark/milvus_benchmark/update.py

@@ -9,6 +9,7 @@ import utils
 
 
 def parse_server_tag(server_tag):
+    """ Parse the yaml file configured by the server """
     # tag format: "8c"/"8c16m"/"8c16m1g"
     if server_tag[-1] == "c":
         p = r"(\d+)c"