Bump jetty from 6.1.19 to 6.1.23 in /testing/itest/callback-two-nodes

Bumps jetty from 6.1.19 to 6.1.23.

---
updated-dependencies:
- dependency-name: org.mortbay.jetty:jetty
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/testing/itest/callback-two-nodes/pom.xml b/testing/itest/callback-two-nodes/pom.xml
index f62d991..227c1d8 100644
--- a/testing/itest/callback-two-nodes/pom.xml
+++ b/testing/itest/callback-two-nodes/pom.xml
@@ -51,7 +51,7 @@
         <dependency>
             <groupId>org.mortbay.jetty</groupId>
             <artifactId>jetty</artifactId>
-            <version>6.1.19</version>
+            <version>6.1.23</version>
         </dependency>
         
         <dependency>