Bump html-proofer from 3.18.8 to 3.19.0

Bumps [html-proofer](https://github.com/gjtorikian/html-proofer) from 3.18.8 to 3.19.0.
- [Release notes](https://github.com/gjtorikian/html-proofer/releases)
- [Commits](https://github.com/gjtorikian/html-proofer/compare/v3.18.8...v3.19.0)

Gemfile

@@ -10,6 +10,6 @@ gem 'jekyll-feed', '~> 0.15.1'
 gem "jekyll-sitemap", "~> 1.4"
 
 group :test do
-    gem 'html-proofer', '~> 3.18.8'
+    gem 'html-proofer', '~> 3.19.0'
     gem 'yaml-lint', '~>0.0.7'
 end

Gemfile.lock

@@ -8,12 +8,12 @@ GEM
     em-websocket (0.5.2)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
-    ethon (0.12.0)
-      ffi (>= 1.3.0)
+    ethon (0.13.0)
+      ffi (>= 1.15.0)
     eventmachine (1.2.7)
-    ffi (1.14.2)
+    ffi (1.15.0)
     forwardable-extended (2.6.0)
-    html-proofer (3.18.8)
+    html-proofer (3.19.0)
       addressable (~> 2.3)
       mercenary (~> 0.3)
       nokogumbo (~> 2.0)
@@ -60,10 +60,10 @@ GEM
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
     mini_portile2 (2.5.0)
-    nokogiri (1.11.1)
+    nokogiri (1.11.3)
       mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
-    nokogumbo (2.0.4)
+    nokogumbo (2.0.5)
       nokogiri (~> 1.8, >= 1.8.4)
     parallel (1.20.1)
     pathutil (0.16.2)
@@ -91,7 +91,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  html-proofer (~> 3.18.8)
+  html-proofer (~> 3.19.0)
   jekyll (~> 4.2.0)
   jekyll-feed (~> 0.15.1)
   jekyll-paginate (~> 1.1.0)