Update to org.powermock 2.0.6

Fixes gh-8296

Author: eleftherias

gradle/dependency-management.gradle

@@ -10,12 +10,12 @@ dependencyManagement {
 		dependency 'opensymphony:sitemesh:2.4.2'
 		dependency 'org.gebish:geb-spock:0.10.0'
 		dependency 'org.jasig.cas:cas-server-webapp:4.2.7'
-		dependency 'org.powermock:powermock-api-mockito2:2.0.5'
-		dependency 'org.powermock:powermock-api-support:2.0.5'
-		dependency 'org.powermock:powermock-core:2.0.5'
-		dependency 'org.powermock:powermock-module-junit4-common:2.0.5'
-		dependency 'org.powermock:powermock-module-junit4:2.0.5'
-		dependency 'org.powermock:powermock-reflect:2.0.5'
+		dependency 'org.powermock:powermock-api-mockito2:2.0.6'
+		dependency 'org.powermock:powermock-api-support:2.0.6'
+		dependency 'org.powermock:powermock-core:2.0.6'
+		dependency 'org.powermock:powermock-module-junit4-common:2.0.6'
+		dependency 'org.powermock:powermock-module-junit4:2.0.6'
+		dependency 'org.powermock:powermock-reflect:2.0.6'
 		dependency 'org.python:jython:2.5.0'
 		dependency 'org.spockframework:spock-core:1.0-groovy-2.4'
 		dependency 'org.spockframework:spock-spring:1.0-groovy-2.4'