deps: update dependency com.google.api.grpc:proto-google-cloud-bigqueryconnection-v1 to v2.5.6 (#2336)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.api.grpc:proto-google-cloud-bigqueryconnection-v1](https://togithub.com/googleapis/java-bigqueryconnection/proto-google-cloud-bigqueryconnection-v1) ([source](https://togithub.com/googleapis/java-bigqueryconnection)) | `2.5.5` -> `2.5.6` | [![age](https://badges.renovateapi.com/packages/maven/com.google.api.grpc:proto-google-cloud-bigqueryconnection-v1/2.5.6/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.api.grpc:proto-google-cloud-bigqueryconnection-v1/2.5.6/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.api.grpc:proto-google-cloud-bigqueryconnection-v1/2.5.6/compatibility-slim/2.5.5)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.api.grpc:proto-google-cloud-bigqueryconnection-v1/2.5.6/confidence-slim/2.5.5)](https://docs.renovatebot.com/merge-confidence/) |

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Author: renovate-bot

pom.xml

@@ -188,7 +188,7 @@
       <dependency>
         <groupId>com.google.api.grpc</groupId>
         <artifactId>proto-google-cloud-bigqueryconnection-v1</artifactId>
-        <version>2.5.5</version>
+        <version>2.5.6</version>
         <scope>test</scope>
       </dependency>
     </dependencies>