Added missing plugin version

pom.xml

@@ -62,9 +62,10 @@
 	</modules>
 	
 	<properties>
-	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<jdk.target>1.8</jdk.target>
 		<jdk.source>1.8</jdk.source>
+		<maven-gpg-plugin.version>1.5</maven-gpg-plugin.version>
 	</properties>
 
 	<build>