update dubbo2.x polaris extension version to 0.2.3

Author: chuntaojun

pom.xml

@@ -38,7 +38,7 @@
 
     <properties>
         <!-- Project revision -->
-        <revision>0.2.3-SNAPSHOT</revision>
+        <revision>0.2.3</revision>
         <timestamp>${maven.build.timestamp}</timestamp>
         <maven.build.timestamp.format>yyyy-MM-dd HH:mm</maven.build.timestamp.format>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -268,4 +268,4 @@
             </snapshots>
         </repository>
     </repositories>
-</project>
+</project>