Update kubeclient 3.1.0 -> 4.0

What does this MR do?

Update kubeclient rubygem dependency ~> 3.1.0 to ~> 4.0 (kubeclient follows SemVer)

The breaking change is dropping support for very old kubernetes version (<= 1.2 no longer works). Full changelog https://github.com/abonas/kubeclient/blob/master/CHANGELOG.md

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.