Bump mockito-core from 2.23.0 to 2.23.4 (#1691)

Bumps [mockito-core](https://github.com/mockito/mockito) from 2.23.0 to 2.23.4.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v2.23.0...v2.23.4)

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

Author: dependabot[bot]

pom.xml

@@ -889,7 +889,7 @@
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
             <scope>test</scope>
-            <version>2.23.0</version>
+            <version>2.23.4</version>
             <exclusions>
                 <exclusion>
                     <artifactId>hamcrest-core</artifactId>