Bump org.asciidoctor:asciidoctorj-pdf from 2.3.14 to 2.3.15

Bumps [org.asciidoctor:asciidoctorj-pdf](https://github.com/asciidoctor/asciidoctorj-pdf) from 2.3.14 to 2.3.15.
- [Release notes](https://github.com/asciidoctor/asciidoctorj-pdf/releases)
- [Changelog](https://github.com/asciidoctor/asciidoctorj-pdf/blob/main/CHANGELOG.adoc)
- [Commits](asciidoctor/asciidoctorj-pdf@v2.3.14...v2.3.15)

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

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

docs/reference/pom.xml

@@ -29,7 +29,7 @@
 
     <properties>
         <asciidoctor.version>3.0.0</asciidoctor.version>
-        <asciidoctorj-pdf.version>2.3.14</asciidoctorj-pdf.version>
+        <asciidoctorj-pdf.version>2.3.15</asciidoctorj-pdf.version>
         <pdf.name>weld-reference.pdf</pdf.name>
         <html.name>index.html</html.name>
         <weld.version>${project.version}</weld.version>