Update dependency org.asciidoctor:asciidoctor-gradle-jvm-epub to v3.3.2 (#142)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

build.gradle

@@ -6,7 +6,7 @@ buildscript {
         classpath "org.grails:grails-gradle-plugin:$grailsGradlePluginVersion"
         classpath 'org.asciidoctor:asciidoctor-gradle-jvm:3.3.2'
         classpath 'org.asciidoctor:asciidoctor-gradle-jvm-pdf:3.1.0'
-        classpath 'org.asciidoctor:asciidoctor-gradle-jvm-epub:3.1.0'
+        classpath 'org.asciidoctor:asciidoctor-gradle-jvm-epub:3.3.2'
         classpath 'org.ajoberstar:gradle-git:1.7.2'
         classpath "org.grails.plugins:hibernate5:${gormHibernateVersion-".RELEASE"}"
         classpath "de.undercouch:gradle-download-task:5.0.1"