[maven-release-plugin] prepare release fluent-logger-0.3.1

Author: komamitsu

pom.xml

@@ -10,7 +10,7 @@
 
   <groupId>org.fluentd</groupId>
   <artifactId>fluent-logger</artifactId>
-  <version>0.3.1-SNAPSHOT</version>
+  <version>0.3.1</version>
   <packaging>jar</packaging>
 
   <name>Fluent Logger for Java</name>