deps: update dependency com.google.errorprone:error_prone_annotations to v2.8.1 (#426)

[![WhiteSource Renovate](https://app.renovatebot.com/images/banner.svg)](https://renovatebot.com)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.errorprone:error_prone_annotations](https://errorprone.info) ([source](https://togithub.com/google/error-prone)) | `2.8.0` -> `2.8.1` | [![age](https://badges.renovateapi.com/packages/maven/com.google.errorprone:error_prone_annotations/2.8.1/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.errorprone:error_prone_annotations/2.8.1/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.errorprone:error_prone_annotations/2.8.1/compatibility-slim/2.8.0)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.errorprone:error_prone_annotations/2.8.1/confidence-slim/2.8.0)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

<details>
<summary>google/error-prone</summary>

### [`v2.8.1`](https://togithub.com/google/error-prone/compare/v2.8.0...v2.8.1)

[Compare Source](https://togithub.com/google/error-prone/compare/v2.8.0...v2.8.1)

</details>

---

### Configuration

📅 **Schedule**: At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box.

---

This PR has been generated by [WhiteSource Renovate](https://renovate.whitesourcesoftware.com). View repository job log [here](https://app.renovatebot.com/dashboard#github/googleapis/java-shared-dependencies).

Author: renovate-bot

pom.xml

@@ -74,7 +74,7 @@
     <iam.version>1.0.14</iam.version>
     <opencensus.version>0.28.0</opencensus.version>
     <findbugs.version>3.0.2</findbugs.version>
-    <errorprone.version>2.8.0</errorprone.version>
+    <errorprone.version>2.8.1</errorprone.version>
     <jackson.version>2.12.4</jackson.version>
     <codec.version>1.15</codec.version>
     <httpcomponents.httpcore.version>4.4.14</httpcomponents.httpcore.version>