Set onos maven plugin version to SNAPSHOT of next release version

Change-Id: Idbbd470aa3d39e716fc8ca4e4f3b6e37c5f42c5c
diff --git a/tools/package/maven-plugin/pom.xml b/tools/package/maven-plugin/pom.xml
index a45a7e9..9ce64d3 100644
--- a/tools/package/maven-plugin/pom.xml
+++ b/tools/package/maven-plugin/pom.xml
@@ -26,7 +26,7 @@
 
     <groupId>org.onosproject</groupId>
     <artifactId>onos-maven-plugin</artifactId>
-    <version>1.12</version>
+    <version>1.13-SNAPSHOT</version>
     <packaging>maven-plugin</packaging>
 
     <description>Maven plugin for packaging ONOS applications or generating