[repo] Refactor README.md

Author: yuzelin

README.md

@@ -1,4 +1,6 @@
-![Paimon](https://paimon.apache.org/assets/paimon_blue.svg)
+![Paimon](https://github.com/apache/paimon/blob/master/docs/static/paimon-simple.png)
+
+[![License](https://img.shields.io/badge/license-Apache%202-4EB1BA.svg)](https://www.apache.org/licenses/LICENSE-2.0.html)
 
 This repo is for Apache Paimon Python SDK.