build(deps-dev): bump html-proofer from 3.16.0 to 5.0.6 in /docs

Bumps [html-proofer](https://github.com/gjtorikian/html-proofer) from 3.16.0 to 5.0.6.
- [Release notes](https://github.com/gjtorikian/html-proofer/releases)
- [Changelog](https://github.com/gjtorikian/html-proofer/blob/main/CHANGELOG.md)
- [Commits](gjtorikian/html-proofer@v3.16.0...v5.0.6)

---
updated-dependencies:
- dependency-name: html-proofer
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

docs/Gemfile.lock

@@ -1,34 +1,43 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (6.0.3.4)
+    Ascii85 (1.1.0)
+    activesupport (6.0.6.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
       zeitwerk (~> 2.2, >= 2.2.2)
-    addressable (2.7.0)
-      public_suffix (>= 2.0.2, < 5.0)
+    addressable (2.8.1)
+      public_suffix (>= 2.0.2, < 6.0)
+    afm (0.2.2)
+    async (2.5.0)
+      console (~> 1.10)
+      io-event (~> 1.1)
+      timers (~> 4.1)
     coffee-script (2.4.1)
       coffee-script-source
       execjs
     coffee-script-source (1.11.1)
     colorator (1.1.0)
     commonmarker (0.17.13)
       ruby-enum (~> 0.5)
-    concurrent-ruby (1.1.7)
+    concurrent-ruby (1.2.2)
+    console (1.16.2)
+      fiber-local
     dnsruby (1.61.4)
       simpleidn (~> 0.1)
-    em-websocket (0.5.2)
+    em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
-      http_parser.rb (~> 0.6.0)
-    ethon (0.12.0)
-      ffi (>= 1.3.0)
+      http_parser.rb (~> 0)
+    ethon (0.16.0)
+      ffi (>= 1.15.0)
     eventmachine (1.2.7)
     execjs (2.7.0)
     faraday (1.0.1)
       multipart-post (>= 1.2, < 3)
-    ffi (1.13.1)
+    ffi (1.15.5)
+    fiber-local (1.0.0)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
     github-pages (209)
@@ -81,20 +90,23 @@ GEM
       octokit (~> 4.0)
       public_suffix (~> 3.0)
       typhoeus (~> 1.3)
-    html-pipeline (2.14.0)
+    hashery (2.1.2)
+    html-pipeline (2.14.3)
       activesupport (>= 2)
       nokogiri (>= 1.4)
-    html-proofer (3.16.0)
+    html-proofer (5.0.6)
       addressable (~> 2.3)
-      mercenary (~> 0.3)
-      nokogumbo (~> 2.0)
-      parallel (~> 1.3)
+      async (~> 2.1)
+      nokogiri (~> 1.13)
+      pdf-reader (~> 2.11)
       rainbow (~> 3.0)
       typhoeus (~> 1.3)
       yell (~> 2.0)
-    http_parser.rb (0.6.0)
+      zeitwerk (~> 2.5)
+    http_parser.rb (0.8.0)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
+    io-event (1.1.7)
     jekyll (3.9.0)
       addressable (~> 2.4)
       colorator (~> 1.0)
@@ -206,37 +218,43 @@ GEM
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
     liquid (4.0.3)
-    listen (3.2.1)
+    listen (3.8.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.8.1)
     minima (2.5.1)
       jekyll (>= 3.5, < 5.0)
       jekyll-feed (~> 0.9)
       jekyll-seo-tag (~> 2.1)
-    minitest (5.14.2)
+    minitest (5.18.0)
     multipart-post (2.1.1)
-    nokogiri (1.10.10)
-      mini_portile2 (~> 2.4.0)
-    nokogumbo (2.0.2)
-      nokogiri (~> 1.8, >= 1.8.4)
+    nokogiri (1.14.2)
+      mini_portile2 (~> 2.8.0)
+      racc (~> 1.4)
     octokit (4.18.0)
       faraday (>= 0.9)
       sawyer (~> 0.8.0, >= 0.5.3)
-    parallel (1.19.2)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
+    pdf-reader (2.11.0)
+      Ascii85 (~> 1.0)
+      afm (~> 0.2.1)
+      hashery (~> 2.0)
+      ruby-rc4
+      ttfunk
     public_suffix (3.1.1)
-    rainbow (3.0.0)
+    racc (1.6.2)
+    rainbow (3.1.1)
     rake (13.0.1)
-    rb-fsevent (0.10.4)
+    rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.4)
+    rexml (3.2.5)
     rouge (3.23.0)
     ruby-enum (0.8.0)
       i18n
+    ruby-rc4 (0.1.5)
     rubyzip (2.3.0)
     safe_yaml (1.0.5)
     sass (3.7.4)
@@ -252,16 +270,18 @@ GEM
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     thread_safe (0.3.6)
+    timers (4.3.5)
+    ttfunk (1.7.0)
     typhoeus (1.4.0)
       ethon (>= 0.9.0)
-    tzinfo (1.2.7)
+    tzinfo (1.2.11)
       thread_safe (~> 0.1)
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.7)
     unicode-display_width (1.7.0)
     yell (2.2.2)
-    zeitwerk (2.4.0)
+    zeitwerk (2.6.7)
 
 PLATFORMS
   ruby