Update dependency asciidoctor to v2.0.26 (#8519)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Kris Stern <[email protected]>

Author: renovate[bot]

Gemfile.lock

@@ -4,7 +4,7 @@ GEM
     addressable (2.8.4)
       public_suffix (>= 2.0.2, < 6.0)
     ansi (1.5.0)
-    asciidoctor (2.0.23)
+    asciidoctor (2.0.26)
     asciidoctor-jenkins-extensions (0.9.0)
       asciidoctor (>= 1.5.5)
       coderay (~> 1.1.1)