Bump com.google.cloud:google-cloud-pubsub in /modules/gcloud

Bumps [com.google.cloud:google-cloud-pubsub](https://github.com/googleapis/java-pubsub) from 1.123.8 to 1.123.13.
- [Release notes](https://github.com/googleapis/java-pubsub/releases)
- [Changelog](https://github.com/googleapis/java-pubsub/blob/main/CHANGELOG.md)
- [Commits](googleapis/java-pubsub@v1.123.8...v1.123.13)

---
updated-dependencies:
- dependency-name: com.google.cloud:google-cloud-pubsub
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]

modules/gcloud/build.gradle

@@ -5,7 +5,7 @@ dependencies {
 
     testImplementation 'com.google.cloud:google-cloud-datastore:2.14.2'
     testImplementation 'com.google.cloud:google-cloud-firestore:3.9.3'
-    testImplementation 'com.google.cloud:google-cloud-pubsub:1.123.8'
+    testImplementation 'com.google.cloud:google-cloud-pubsub:1.123.13'
     testImplementation 'com.google.cloud:google-cloud-spanner:6.38.2'
     testImplementation 'com.google.cloud:google-cloud-bigtable:2.20.3'
     testImplementation 'org.assertj:assertj-core:3.24.2'