ZOOKEEPER-3794: upgrade netty to address CVE-2020-11612
Latest owasp runs are flagging this. Simple upgrade to the current latest version of netty 4.1.x codeline.
Change-Id: I3defe8a731a2bf22abbd154e7d51054cb62aaa64
Author: Patrick Hunt <phunt@apache.org>
Reviewers: Enrico Olivelli <eolivelli@apache.org>
Closes #1319 from phunt/ZOOKEEPER-3794