Compatibility with newer Java versions
I try to use the `org.asciidoctor.jvm.gems` plugin which uses this plugin under the hood.
When executing the `AsciidoctorGemPrepare` task which extends `AbstractGemPrepareTask` while executing Gradle with Java 17, you are warned with
```plain
WARN FilenoUtil : Native subprocess control requires open access to the JDK IO subsystem
Pass '--add-opens java.base/sun.nio.ch=ALL-UNNAMED --add-opens java.base/java.io=ALL-UNNAMED' to enable.
```
which is not "easily" work-aroundable due to #14.
issue