Update dependency com.slack.eithernet:eithernet to v1.9.0

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
com.slack.eithernet:eithernet	1.8.1 -> 1.9.0

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Release Notes

slackhq/eithernet (com.slack.eithernet:eithernet)

### [`v1.9.0`](https://togithub.com/slackhq/eithernet/blob/HEAD/CHANGELOG.md#190) [Compare Source](https://togithub.com/slackhq/eithernet/compare/1.8.1...1.9.0) *2024-06-05* - Update to Kotlin `2.0.0`.

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Configuration

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