test(deps): update dependency com.google.protobuf:protoc to v3.23.4 (#1795)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.protobuf:protoc](https://developers.google.com/protocol-buffers/) ([source](https://togithub.com/protocolbuffers/protobuf)) | `3.23.2` -> `3.23.4` | [![age](https://badges.renovateapi.com/packages/maven/com.google.protobuf:protoc/3.23.4/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.protobuf:protoc/3.23.4/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.protobuf:protoc/3.23.4/compatibility-slim/3.23.2)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.protobuf:protoc/3.23.4/confidence-slim/3.23.2)](https://docs.renovatebot.com/merge-confidence/) |

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### Release Notes

<details>
<summary>protocolbuffers/protobuf (com.google.protobuf:protoc)</summary>

### [`v3.23.3`](https://togithub.com/protocolbuffers/protobuf/compare/v3.23.2...v3.23.3)

</details>

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Author: renovate-bot

google-cloud-bigtable/pom.xml

@@ -39,7 +39,7 @@
 
     <!-- These are needed to compile the protobuf used by Changestream merging acceptance test. -->
     <test-protoc-grpc.version>1.56.1</test-protoc-grpc.version>
-    <test-protoc.version>3.23.2</test-protoc.version>
+    <test-protoc.version>3.23.4</test-protoc.version>
   </properties>
 
   <dependencyManagement>