Bump zookeeper version to fix apache/openwhisk#5564

[francescotimperioss]

Bump zookeeper version to allow usage of legacy LB based setup

Description

This OR fixes a call not found found error attempting to setup OW2 with legacy LB, even if this is not anymore the recommended setup.

Related issue and scope

• [ X] I opened an issue to propose and discuss this change (Forcing Legacy LB results in class not found exception error linked to zookeeper #5564)

My changes affect the following components

• API
• Controller
• Message Bus (e.g., Kafka)
• Loadbalancer
• Scheduler
• [X ] Invoker
• Intrinsic actions (e.g., sequences, conductors)
• Data stores (e.g., CouchDB)
• Tests
• Deployment
• CLI
• General tooling
• Documentation

Types of changes

• [X ] Bug fix (generally a non-breaking change which closes an issue).
• Enhancement or new feature (adds new functionality).
• Breaking change (a bug fix or enhancement which changes existing behavior).

Checklist:

• [ X] I signed an Apache CLA.
• I reviewed the style guides and followed the recommendations (Travis CI will check :).
• I added tests to cover my changes.
• My changes require further changes to the documentation.
• I updated the documentation where necessary.