zookeeper 3.7.x is out of support and will stop receiving security fixes
in ~ 3 months (on 2024-01-19). 3.8.X should be in support for some time
longer.
log4j.properties was removed, but a logback config was added.
Change-Id: Ifb6af02abc9e889534f6620b296a9c5c8f0b8b6e
Signed-off-by: Neil Hanlon <neil@shrug.pw>