Bump asciidoctor from 2.0.21 to 2.0.22

Bumps [asciidoctor](https://github.com/asciidoctor/asciidoctor) from 2.0.21 to 2.0.22.
- [Release notes](https://github.com/asciidoctor/asciidoctor/releases)
- [Changelog](https://github.com/asciidoctor/asciidoctor/blob/main/CHANGELOG.adoc)
- [Commits](asciidoctor/asciidoctor@v2.0.21...v2.0.22)

---
updated-dependencies:
- dependency-name: asciidoctor
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -8,7 +8,7 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    asciidoctor (2.0.21)
+    asciidoctor (2.0.22)
     ast (2.4.2)
     commonmarker (0.23.10)
     docopt (0.6.1)