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.

[francescotimperioss]

After rebasing this PR with code from master branch I still get these unit Test failing, linked to ElasticSearch and i don't really understand how this could be related to the scope of the changes of this PR.

Failed tests * [5]ElasticSearchActivationStoreTests. [6]ElasticSearchActivationStore countActivationsInNamespace should count with option name * [7]ElasticSearchActivationStoreTests. [8]ElasticSearchActivationStore countActivationsInNamespace should count with since and upto * [9]ElasticSearchActivationStoreTests. [10]ElasticSearchActivationStore countActivationsInNamespace should count with skip * [11]ElasticSearchActivationStoreTests. [12]ElasticSearchActivationStore countActivationsInNamespace should should count all created activations * [13]ElasticSearchActivationStoreTests. [14]ElasticSearchActivationStore listActivationsInNamespace should find all entities * [15]ElasticSearchActivationStoreTests. [16]ElasticSearchActivationStore listActivationsInNamespace should support since and upto filters * [17]ElasticSearchActivationStoreTests. [18]ElasticSearchActivationStore listActivationsInNamespace should support skipping results

I also see that Unit test fails also within subsequent scheduled build execution, without any code changes. An idea about how to fix this issue? This is preventing the Apache OpenServerless to use a deployment mode that it is not requiring the Scheduler, which for some scenarios it is still a good option.