fix license name (#26)

pom.xml

@@ -24,7 +24,7 @@ See the Mulan PSL v2 for more details.
 
   <licenses>
     <license>
-      <name>Mulan Public License，Version 2</name>
+      <name>Mulan Permissive Software License，Version 2</name>
       <url>http://license.coscl.org.cn/MulanPSL2/</url>
     </license>
   </licenses>