[maven-release-plugin] prepare release fess-10.3.1

pom.xml

@@ -3,7 +3,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.codelibs.fess</groupId>
 	<artifactId>fess</artifactId>
-	<version>10.3.1-SNAPSHOT</version>
+	<version>10.3.1</version>
 	<packaging>war</packaging>
 	<name>Fess</name>
 	<description>Fess is Full tExt Search System.</description>