upgraded to gradle 4.6 which is the minimum needed for junit5 test running support

Author: johnscancella

gradle/wrapper/gradle-wrapper.jar

@@ -1,5 +1,5 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.2.1-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-bin.zip
 zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists