deps(deps): Bump the testing group with 4 updates

Bumps the testing group with 4 updates: [org.junit:junit-bom](https://github.com/junit-team/junit-framework), [org.assertj:assertj-core](https://github.com/assertj/assertj), [org.mockito:mockito-core](https://github.com/mockito/mockito) and [org.mockito:mockito-junit-jupiter](https://github.com/mockito/mockito).


Updates `org.junit:junit-bom` from 5.11.4 to 6.0.2
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](junit-team/junit-framework@r5.11.4...r6.0.2)

Updates `org.assertj:assertj-core` from 3.27.3 to 3.27.7
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](assertj/assertj@assertj-build-3.27.3...assertj-build-3.27.7)

Updates `org.mockito:mockito-core` from 5.15.2 to 5.21.0
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.15.2...v5.21.0)

Updates `org.mockito:mockito-junit-jupiter` from 5.15.2 to 5.21.0
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.15.2...v5.21.0)

Updates `org.mockito:mockito-junit-jupiter` from 5.15.2 to 5.21.0
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.15.2...v5.21.0)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-version: 6.0.2
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: testing
- dependency-name: org.assertj:assertj-core
  dependency-version: 3.27.7
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: testing
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: testing
- dependency-name: org.mockito:mockito-junit-jupiter
  dependency-version: 5.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: testing
- dependency-name: org.mockito:mockito-junit-jupiter
  dependency-version: 5.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: testing
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pom.xml

@@ -76,9 +76,9 @@
         <akka-javasdk.version>3.0.2</akka-javasdk.version>
 
         <!-- Test dependency versions -->
-        <junit.version>5.11.4</junit.version>
-        <assertj.version>3.27.3</assertj.version>
-        <mockito.version>5.15.2</mockito.version>
+        <junit.version>6.0.2</junit.version>
+        <assertj.version>3.27.7</assertj.version>
+        <mockito.version>5.21.0</mockito.version>
 
         <!-- Plugin versions -->
         <maven-compiler-plugin.version>3.13.0</maven-compiler-plugin.version>