Update README.md

Author: maskleo

README.md

@@ -123,4 +123,7 @@
 ## 高清英文版 PDF[下载](https://github.com/maskleo/Java-Generics-and-Collections/files/1634266/Java.pdf)
 
 ## LICENSE
-![](LICENSE.png)
+
+### [CC-BY-SA-3.0](https://creativecommons.org/licenses/by-nc-sa/3.0/cn/)
+
+[![](LICENSE.png)](https://creativecommons.org/licenses/by-nc-sa/3.0/cn/)