Update Mockito to 2.13.0

Author: nhaarman

mockito-kotlin/build.gradle

@@ -25,7 +25,7 @@ repositories {
 
 dependencies {
     compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
-    compile "org.mockito:mockito-core:2.12.0"
+    compile "org.mockito:mockito-core:2.13.0"
 
     /* Tests */
     testCompile "junit:junit:4.12"