Bump org.mockito:mockito-core from 5.20.0 to 5.21.0

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] <support@github.com>

Author: dependabot[bot]

build.gradle

@@ -29,7 +29,7 @@ repositories {
 dependencies {
     implementation 'com.beust:jcommander:1.82'
     implementation 'commons-io:commons-io:2.21.0'
-    testImplementation 'org.mockito:mockito-core:5.20.0'
+    testImplementation 'org.mockito:mockito-core:5.21.0'
     testImplementation 'junit:junit:4.13.2'
 }