Bump com.google.api.grpc:proto-google-common-protos (#534)[skip ci]

Bumps [com.google.api.grpc:proto-google-common-protos](https://github.com/googleapis/sdk-platform-java) from 2.67.0 to 2.68.0.
- [Release notes](https://github.com/googleapis/sdk-platform-java/releases)
- [Changelog](https://github.com/googleapis/sdk-platform-java/blob/main/CHANGELOG.md)
- [Commits](googleapis/sdk-platform-java@v2.67.0...v2.68.0)

---
updated-dependencies:
- dependency-name: com.google.api.grpc:proto-google-common-protos
  dependency-version: 2.68.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pom.xml

@@ -14,7 +14,7 @@
         <module>support-lite</module>
     </modules>
     <properties>
-        <grpc.api.version>2.67.0</grpc.api.version>
+        <grpc.api.version>2.68.0</grpc.api.version>
         <gson.version>2.13.2</gson.version>
         <guava.version>33.5.0-jre</guava.version>
         <jreleaser-maven-plugin.version>1.18.0</jreleaser-maven-plugin.version>