Bump mockito-core from 3.12.4 to 4.0.0 in /core

Bumps [mockito-core](https://github.com/mockito/mockito) from 3.12.4 to 4.0.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v3.12.4...v4.0.0)

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

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

Author: dependabot[bot]

core/build.gradle

@@ -93,7 +93,7 @@ dependencies {
     testImplementation 'com.rabbitmq:amqp-client:5.13.1'
     testImplementation 'org.mongodb:mongo-java-driver:3.12.10'
 
-    testImplementation ('org.mockito:mockito-core:3.12.4') {
+    testImplementation ('org.mockito:mockito-core:4.0.0') {
         exclude(module: 'hamcrest-core')
     }
     // Synthetic JAR used for MountableFileTest and DirectoryTarResourceTest