Bump mockito-core from 2.1.0 to 3.6.28

Bumps [mockito-core](https://github.com/mockito/mockito) from 2.1.0 to 3.6.28.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v2.1.0...v3.6.28)

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index 5cddd32..216e468 100644
--- a/pom.xml
+++ b/pom.xml
@@ -419,7 +419,7 @@
             <dependency>
                 <groupId>org.mockito</groupId>
                 <artifactId>mockito-core</artifactId>
-                <version>2.1.0</version>
+                <version>3.6.28</version>
             </dependency>
             <dependency>
                 <groupId>com.sun.xml.ws</groupId>