Added SonarCloud integration (#3698)

Updated gradle wrapper to 4.8

build.gradle

@@ -30,6 +30,11 @@ buildscript {
         classpath 'net.minecraftforge.gradle:ForgeGradle:2.3-SNAPSHOT'
     }
 }
+
+plugins {
+  id "org.sonarqube" version "2.6"
+}
+
 apply plugin: 'net.minecraftforge.gradle.forge'
 
 repositories {
@@ -112,4 +117,4 @@ processResources
 
     // move access transformer to META-INF
     rename '(.+_at.cfg)', 'META-INF/$1'
-}
+}