Bump org.asciidoctor:asciidoctorj-pdf from 1.5.3 to 2.3.17

Bumps [org.asciidoctor:asciidoctorj-pdf](https://github.com/asciidoctor/asciidoctorj-pdf) from 1.5.3 to 2.3.17.
- [Release notes](https://github.com/asciidoctor/asciidoctorj-pdf/releases)
- [Changelog](https://github.com/asciidoctor/asciidoctorj-pdf/blob/main/CHANGELOG.adoc)
- [Commits](asciidoctor/asciidoctorj-pdf@v1.5.3...v2.3.17)

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

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

spec/pom.xml

@@ -86,7 +86,7 @@
         <site.output.dir>${project.build.directory}/staging</site.output.dir>
         <maven.site.skip>true</maven.site.skip>
         <asciidoctorj.version>2.5.13</asciidoctorj.version>
-        <asciidoctorj.pdf.version>1.5.3</asciidoctorj.pdf.version>
+        <asciidoctorj.pdf.version>2.3.17</asciidoctorj.pdf.version>
         <jruby.version>9.3.14.0</jruby.version>
         <!-- status: DRAFT, BETA, etc., or blank for final -->
         <status>DRAFT</status>