Fix onos-dependencies version to aling with deps.json

Change-Id: I334e33829348b9b74af63e4b73782097fbcf7976
diff --git a/lib/pom.xml b/lib/pom.xml
index fa8c8f6..31d3c13 100644
--- a/lib/pom.xml
+++ b/lib/pom.xml
@@ -116,7 +116,7 @@
             <dependency>
                 <groupId>com.googlecode.concurrent-trees</groupId>
                 <artifactId>concurrent-trees</artifactId>
-                <version>2.4.0</version>
+                <version>2.6.0</version>
             </dependency>
 
             <dependency>