Update README.md

Author: dongeforever

README.md

@@ -10,7 +10,7 @@ At present, this SDK supports
 
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 ## How to use
-* Step-by-step instruction are provided in [RocketMQ Client Python Introduction](https://github.com/apache/rocketmq-client-python/doc/Introduction.md)
+* Step-by-step instruction are provided in [RocketMQ Client Python Introduction](https://github.com/apache/rocketmq-client-python/blob/master/doc/Introduction.md)
 * Consult [RocketMQ Quick Start](https://rocketmq.apache.org/docs/quick-start/) to setup rocketmq broker and nameserver.
 
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