Bump html-pipeline from 2.11.1 to 2.12.0

Bumps [html-pipeline](https://github.com/jch/html-pipeline) from 2.11.1 to 2.12.0.
- [Release notes](https://github.com/jch/html-pipeline/releases)
- [Changelog](https://github.com/jch/html-pipeline/blob/master/CHANGELOG.md)
- [Commits](gjtorikian/html-pipeline@v2.11.1...v2.12.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

Gemfile.lock

@@ -81,7 +81,7 @@ GEM
       octokit (~> 4.0)
       public_suffix (~> 3.0)
       typhoeus (~> 1.3)
-    html-pipeline (2.11.1)
+    html-pipeline (2.12.0)
       activesupport (>= 2)
       nokogiri (>= 1.4)
     html-proofer (3.11.1)