build(gradle): remove error prone plugin which does not support Java 9

build.gradle

@@ -11,7 +11,6 @@ plugins {
     // Sub project plugins
     id 'com.github.sherter.google-java-format' version '0.6' apply false
     id 'nebula.lint' version '8.3.1' apply false
-    id 'net.ltgt.errorprone' version '0.0.11' apply false
 }
 
 description = "Apereo uPortal $version"
@@ -50,11 +49,6 @@ allprojects {
     apply plugin: 'idea'
     apply plugin: 'nebula.lint'
     apply plugin: 'com.github.sherter.google-java-format'
-    apply plugin: 'net.ltgt.errorprone'
-
-    dependencies {
-      errorprone 'com.google.errorprone:error_prone_core:2.1.1'
-    }
 
     sourceCompatibility = 1.8
 
@@ -97,8 +91,6 @@ subprojects {
     apply plugin: 'signing'
     apply plugin: 'maven-publish'
     apply plugin: 'com.github.sherter.google-java-format'
-    apply plugin: 'net.ltgt.errorprone'
-
 
     /*======== Dependency Management ========**/
     repositories {