Jetcd will drop java 8

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- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

### Search before asking

- [X] I have searched in the [issues](https://github.com/apache/kyuubi/issues?q=is%3Aissue) and found no similar issues.

### Describe the feature

Question
Hi kyuubi community, just for note that Jetcd will drop java 8, please check https://github.com/etcd-io/jetcd/issues/1218

### Motivation

_No response_

### Describe the solution

_No response_

### Additional context

_No response_

### Are you willing to submit PR?

- [ ] Yes. I would be willing to submit a PR with guidance from the Kyuubi community to improve.
- [ ] No. I cannot submit a PR at this time.

Start by reading the linked Jetcd issue 1218, then inspect Kyuubi's Java compatibility and Jetcd dependency configuration. Determine the impact of Jetcd dropping Java 8 and document or implement the required compatibility change, with the project’s existing checks confirming that the supported build still works.

Written by the indexing model from the issue text.