Update to Gradle 4.6

Only thing of interest really is that the Jacoco Gradle plugin was bumped
to 0.8.0, which requires org.ow2.asm:asm:6.0.

Fixes: gh-5077

gradle/dependency-management.gradle

@@ -169,7 +169,7 @@ dependencyManagement {
 		dependency 'org.mockito:mockito-core:2.13.0'
 		dependency 'org.objenesis:objenesis:2.6'
 		dependency 'org.openid4java:openid4java-nodeps:0.9.6'
-		dependency 'org.ow2.asm:asm:5.0.4'
+		dependency 'org.ow2.asm:asm:6.0'
 		dependency 'org.reactivestreams:reactive-streams:1.0.1'
 		dependency 'org.seleniumhq.selenium:htmlunit-driver:2.29.2'
 		dependency 'org.seleniumhq.selenium:selenium-api:3.8.1'

gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.5.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-bin.zip