Update netty to 4.1.68.Final

Author: gjmwoods

pom.xml

@@ -30,7 +30,7 @@
     <!-- Please note that when updating this dependency -->
     <!-- (i.e. due to a security vulnerability or bug) that the -->
     <!-- corresponding server dependency also needs updating.-->
-    <netty-handler.version>4.1.66.Final</netty-handler.version>
+    <netty-handler.version>4.1.68.Final</netty-handler.version>
     <!-- Please note that when updating this dependency -->
     <!-- (i.e. due to a security vulnerability or bug) that the -->
     <!-- corresponding server dependency also needs updating.-->