Updated asciidoctor gradle configuration for gradle 7

After upgrading to gradle 7 some problems occured. Here’s the minimum build.gradle to make it work:

apply plugin: 'org.asciidoctor.jvm.convert'

dependencies {
    docs "org.codehaus.groovy:groovy-all:${groovyVersion}"
}
#either jar
jar {
    finalizedBy(asciidoctor)
}
#or war
war {
    finalizedBy(asciidoctor)
}

asciidoctor {
    baseDir("${project.rootDir}/src/docs/asciidoc")
}