Upgrade to Mockito 2.28.2

Closes gh-17189

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -147,7 +147,7 @@
 		<mariadb.version>2.4.1</mariadb.version>
 		<micrometer.version>1.1.4</micrometer.version>
 		<mimepull.version>1.9.11</mimepull.version>
-		<mockito.version>2.27.0</mockito.version>
+		<mockito.version>2.28.2</mockito.version>
 		<mongo-driver-reactivestreams.version>1.11.0</mongo-driver-reactivestreams.version>
 		<mongodb.version>3.11.0-beta3</mongodb.version>
 		<mssql-jdbc.version>6.4.0.jre8</mssql-jdbc.version>