chore(deps): bump org.mockito:mockito-core in /java-gradle

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.20.0 to 5.21.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.20.0...v5.21.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

java-gradle/build.gradle

@@ -13,7 +13,7 @@ dependencies {
     implementation 'com.rabbitmq:amqp-client:5.28.0'
     implementation 'org.slf4j:slf4j-simple:2.0.17'
     testImplementation 'org.assertj:assertj-core:3.27.6'
-    testImplementation 'org.mockito:mockito-core:5.20.0'
+    testImplementation 'org.mockito:mockito-core:5.21.0'
     testImplementation 'io.dropwizard.metrics:metrics-core:4.2.37'
     testImplementation 'org.junit.jupiter:junit-jupiter-api:6.0.0'
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:6.0.0'