devel/zookeeper: update 3.5.5 -> 3.6.1
devel/libzookeeper: update 3.5.5 -> 3.6.1

• submitter becomes maintainer

PR: 246920
Submitted by: Dmitry Wagin <dmitry.wagin@ya.ru>
Approved by: skreuzer (maintainer)
Relnotes: https://zookeeper.apache.org/doc/r3.6.1/releasenotes.html