Bump org.mockito:mockito-core from 5.20.0 to 5.21.0 in /SimpleAPI

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:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

SimpleAPI/pom.xml

@@ -200,7 +200,7 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.20.0</version>
+            <version>5.21.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>