Bump mockito-core from 1.9.5 to 2.28.2

diff --git a/pom.xml b/pom.xml
index 2488cf6..3c590c6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -128,7 +128,7 @@
     <dependency>
       <groupId>org.mockito</groupId>
       <artifactId>mockito-core</artifactId>
-      <version>1.9.5</version>
+      <version>2.28.2</version>
       <scope>test</scope>
     </dependency>
     <dependency>