Bump asciidoctor-maven-plugin from 2.2.3 to 2.2.4

Bumps [asciidoctor-maven-plugin](https://github.com/asciidoctor/asciidoctor-maven-plugin) from 2.2.3 to 2.2.4.
- [Release notes](https://github.com/asciidoctor/asciidoctor-maven-plugin/releases)
- [Changelog](https://github.com/asciidoctor/asciidoctor-maven-plugin/blob/asciidoctor-maven-plugin-2.2.4/CHANGELOG.adoc)
- [Commits](asciidoctor/asciidoctor-maven-plugin@asciidoctor-maven-plugin-2.2.3...asciidoctor-maven-plugin-2.2.4)

---
updated-dependencies:
- dependency-name: org.asciidoctor:asciidoctor-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

pom.xml

@@ -194,7 +194,7 @@
     <profile>
       <id>pdfs</id>
       <properties>
-        <asciidoctor.maven.plugin.version>2.2.3</asciidoctor.maven.plugin.version>
+        <asciidoctor.maven.plugin.version>2.2.4</asciidoctor.maven.plugin.version>
         <asciidoctorj.pdf.version>2.3.9</asciidoctorj.pdf.version>
         <asciidoctorj.version>2.5.10</asciidoctorj.version>
         <jruby.version>9.4.3.0</jruby.version>