Use gradle-versions-plugin to check for dependency updates.

+ This plugin adds the "dependencyUpdates" Gradle task.
+ Plugin website: https://github.com/ben-manes/gradle-versions-plugin

build.gradle

@@ -3,6 +3,7 @@ plugins {
     id "idea"
     id "org.jetbrains.intellij" version "0.4.13"
     id "com.github.johnrengelman.shadow" version "5.1.0"
+    id "com.github.ben-manes.versions" version "0.33.0"
 }
 
 sourceCompatibility = javaVersion