Upgrade gradle and java versions

Author: pontusmelke

build.gradle

@@ -4,16 +4,16 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath 'com.github.jengelman.gradle.plugins:shadow:1.2.3'
-        classpath 'info.solidsoft.gradle.pitest:gradle-pitest-plugin:1.1.9'
+        classpath 'com.github.jengelman.gradle.plugins:shadow:4.0.2'
+        classpath 'info.solidsoft.gradle.pitest:gradle-pitest-plugin:1.4.0'
     }
 }
 
 allprojects {
     apply plugin: 'java'
 
-    sourceCompatibility = 1.8
-    targetCompatibility = 1.8
+    sourceCompatibility = 11
+    targetCompatibility = 11
 
     tasks.withType(JavaCompile) {
         options.incremental = true

gradle/integration-test.gradle

@@ -18,7 +18,7 @@ dependencies {
 
 // Define integration test task
 task integrationTest(type: Test) {
-  testClassesDir = sourceSets.integrationTest.output.classesDir
+  testClassesDirs = sourceSets.integrationTest.output.classesDirs
   classpath = sourceSets.integrationTest.runtimeClasspath
 }
 

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-3.4.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.2.1-bin.zip