Bump @springio/antora-extensions from 1.14.11 to 1.14.12 in /antora

Bumps [@springio/antora-extensions](https://github.com/spring-io/antora-extensions) from 1.14.11 to 1.14.12.
- [Changelog](https://github.com/spring-io/antora-extensions/blob/main/CHANGELOG.adoc)
- [Commits](spring-io/antora-extensions@v1.14.11...v1.14.12)

---
updated-dependencies:
- dependency-name: "@springio/antora-extensions"
  dependency-version: 1.14.12
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]