Update wrapper task configuration syntax for the upcoming Gradle 5.0.

build.gradle

-import org.gradle.api.tasks.wrapper.Wrapper
-import org.gradle.api.tasks.wrapper.Wrapper.DistributionType
-
 plugins {
     id 'java'
     id 'idea'
@@ -26,8 +23,8 @@ dependencies {
     compile 'commons-io:commons-io:2.5'
 }
 
-task wrapper(type: Wrapper) {
-    distributionType DistributionType.ALL
+wrapper {
+    distributionType Wrapper.DistributionType.ALL
     gradleVersion '4.8.1'
 }