ZOOKEEPER-4272: Upgrade Netty library to > 4.1.60 due to security vulnerability CVE-2021-21295
Upgraded Netty library to 4.1.60
Author: Ayush Mantri <aayushmantri@gmail.com>
Reviewers: Enrico Olivelli <eolivelli@apache.org>, Mohammad Arshad <arshad@apache.org>
Closes #1669 from ayushmantri/ZOOKEEPER-4272