bump yang-tools version to 2.4.7

Change-Id: I0a257b8b524cd7f6e606d57e6d1a3a5388646ebe
diff --git a/lib/pom.xml b/lib/pom.xml
index 41598a7..0e7b3f8 100644
--- a/lib/pom.xml
+++ b/lib/pom.xml
@@ -40,7 +40,7 @@
         <netty4.version>4.1.8.Final</netty4.version>
         <openflowj.version>3.2.1.onos</openflowj.version>
         <onos-maven-plugin.version>1.12</onos-maven-plugin.version>
-        <onos-yang-tools.version>2.4.1</onos-yang-tools.version>
+        <onos-yang-tools.version>2.4.7</onos-yang-tools.version>
         <osgi.version>5.0.0</osgi.version>
         <karaf.version>3.0.8</karaf.version>
         <jersey.version>2.26</jersey.version>