Bump @springio/asciidoctor-extensions (#1705)

Bumps [@springio/asciidoctor-extensions](https://github.com/spring-io/asciidoctor-extensions) from 1.0.0-alpha.10 to 1.0.0-alpha.13.
- [Changelog](https://github.com/spring-io/asciidoctor-extensions/blob/main/CHANGELOG.adoc)
- [Commits](https://github.com/spring-io/asciidoctor-extensions/compare/v1.0.0-alpha.10...v1.0.0-alpha.13)

---
updated-dependencies:
- dependency-name: "@springio/asciidoctor-extensions"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -5,7 +5,7 @@
     "@antora/collector-extension": "1.0.0-alpha.3",
     "@asciidoctor/tabs": "1.0.0-beta.6",
     "@springio/antora-extensions": "1.11.1",
-    "@springio/asciidoctor-extensions": "1.0.0-alpha.10",
+    "@springio/asciidoctor-extensions": "1.0.0-alpha.13",
     "asciidoctor-kroki": "0.18.1"
   }
 }