Update HorizontalPodAutoscaler to the v2 CRD

[sebagomez]

The helm chart fails to apply on "newer" versions of Kubernetes because autoscaling/v2beta is no longer available

References

https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#support-for-resource-metrics

Submitter checklist

• [ x] Recommended: Join WireMock Slack to get any help in #help-contributing or a project-specific channel like #wiremock-java
• [ x] The PR request is well described and justified, including the body and the references
• [ x] The PR title represents the desired changelog entry
• [ x] The repository's code style is followed (see the contributing guide)
• [ x] Test coverage that demonstrates that the change works as expected
• [ x] For new features, there's necessary documentation in this pull request or in a subsequent PR to wiremock.org

[gitkent]

@sebagomez thanks for your PR. Please check linting error in CI.

[DanielFran]

@sebagomez @gitkent Maybe also update the chart with latest app version?
appVersion: "3.8.0" > appVersion: "3.10.0"?