Upgrade to zookeeper 3.6.2

solr is using netty packages with versions 4.1.50.

An explicit dependency 'zookeeper', which is listed in versions.props, is not at its latest version 3.6.2, and so may use older less optimized version of netty packages through zookeeper's old version 3.6.1

• Netty 4.1.50 is having support and optimization for arm64 platform ( Refer netty release notes ) and using this version makes it efficient for arm64 platform also.
• Zookeeper upgraded to netty 4.1.50 in a recent PR with ticket for the same.