build(deps-dev): bump html-proofer from 3.16.0 to 3.17.0 in /docs

Bumps [html-proofer](https://github.com/gjtorikian/html-proofer) from 3.16.0 to 3.17.0.
- [Release notes](https://github.com/gjtorikian/html-proofer/releases)
- [Commits](https://github.com/gjtorikian/html-proofer/compare/v3.16.0...v3.17.0)

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

docs/Gemfile.lock

@@ -84,7 +84,7 @@ GEM
     html-pipeline (2.14.0)
       activesupport (>= 2)
       nokogiri (>= 1.4)
-    html-proofer (3.16.0)
+    html-proofer (3.17.0)
       addressable (~> 2.3)
       mercenary (~> 0.3)
       nokogumbo (~> 2.0)
@@ -224,7 +224,7 @@ GEM
     octokit (4.18.0)
       faraday (>= 0.9)
       sawyer (~> 0.8.0, >= 0.5.3)
-    parallel (1.19.2)
+    parallel (1.20.0)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (3.1.1)