deps: update dependency com.google.auto.value:auto-value to v1.8.1 (#219)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.auto.value:auto-value](https://togithub.com/google/auto) | `1.8` -> `1.8.1` | [![age](https://badges.renovateapi.com/packages/maven/com.google.auto.value:auto-value/1.8.1/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.auto.value:auto-value/1.8.1/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.auto.value:auto-value/1.8.1/compatibility-slim/1.8)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.auto.value:auto-value/1.8.1/confidence-slim/1.8)](https://docs.renovatebot.com/merge-confidence/) |

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