Update dependency org.asciidoctor:asciidoctor-gradle-jvm to v4 (#342)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

build.gradle

@@ -4,7 +4,7 @@ buildscript {
     }
     dependencies {
         classpath "org.grails:grails-gradle-plugin:$grailsGradlePluginVersion"
-        classpath "org.asciidoctor:asciidoctor-gradle-jvm:3.3.2"
+        classpath "org.asciidoctor:asciidoctor-gradle-jvm:4.0.2"
     }
 }