chore(deps): bump asciidoctorj-diagram from 2.2.3 to 2.2.9

Bumps [asciidoctorj-diagram](https://github.com/asciidoctor/asciidoctorj-diagram) from 2.2.3 to 2.2.9.
- [Release notes](https://github.com/asciidoctor/asciidoctorj-diagram/releases)
- [Commits](asciidoctor/asciidoctorj-diagram@v2.2.3...v2.2.9)

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

Signed-off-by: dependabot[bot] <support@github.com>

docs/pom.xml

@@ -19,7 +19,7 @@
         <maven.compiler.target>11</maven.compiler.target>
         <asciidoctor.maven.plugin.version>2.2.2</asciidoctor.maven.plugin.version>
         <asciidoctorj.version>2.5.7</asciidoctorj.version>
-        <asciidoctorj.diagram.version>2.2.3</asciidoctorj.diagram.version>
+        <asciidoctorj.diagram.version>2.2.9</asciidoctorj.diagram.version>
         <jruby.version>9.4.2.0</jruby.version>
     </properties>