Merge pull request #1560 from progit/dependabot/bundler/asciidoctor-2.0.12

Update asciidoctor requirement from 2.0.11 to 2.0.12

Author: ben

Gemfile

@@ -1,7 +1,7 @@
 source 'https://rubygems.org'
 
 gem 'rake', ' 13.0.1'
-gem 'asciidoctor', '2.0.11'
+gem 'asciidoctor', '2.0.12'
 
 gem 'json', '2.3.1'
 gem 'awesome_print', '1.8.0'