Update mockito-3-4 to 3.2.6.0 (#265)

Author: scala-steward

project/Dependencies.scala

@@ -2,7 +2,7 @@ import sbt._
 
 object Version {
   val logback   = "1.2.3"
-  val mockito   = "3.2.5.0"
+  val mockito   = "3.2.6.0"
   val scalaTest = "3.2.5"
   val slf4j     = "1.7.30"
 }