Update README.md (#210)

* Update README.md

Fix typo in the README python SDK example.

* Fix the typo in readme.cn

README.cn.md

@@ -75,7 +75,7 @@ import random
 from visualdl import LogWriter
 
 logdir = "./tmp"
-logger = LogWriter(dir, sync_cycle=10)
+logger = LogWriter(logdir, sync_cycle=10)
 
 # mark the components with 'train' label.
 with logger.mode("train"):

README.md

@@ -84,7 +84,7 @@ import random
 from visualdl import LogWriter
 
 logdir = "./tmp"
-logger = LogWriter(dir, sync_cycle=10)
+logger = LogWriter(logdir, sync_cycle=10)
 
 # mark the components with 'train' label.
 with logger.mode("train"):