Remove test dependencies

Gemfile

@@ -1,7 +1,3 @@
 source "https://rubygems.org"
 
 gem "jekyll"
-
-group :test do
-    gem "html-proofer"
-end

Gemfile.lock

@@ -1,82 +1,66 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (5.0.1)
-      concurrent-ruby (~> 1.0, >= 1.0.2)
-      i18n (~> 0.7)
-      minitest (~> 5.1)
-      tzinfo (~> 1.1)
-    addressable (2.5.0)
-      public_suffix (~> 2.0, >= 2.0.2)
+    addressable (2.5.2)
+      public_suffix (>= 2.0.2, < 4.0)
     colorator (1.1.0)
-    colored (1.2)
     concurrent-ruby (1.0.5)
-    ethon (0.10.1)
-      ffi (>= 1.3.0)
-    ffi (1.9.17)
-    ffi (1.9.17-x64-mingw32)
+    em-websocket (0.5.1)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0.6.0)
+    eventmachine (1.2.5)
+    eventmachine (1.2.5-x64-mingw32)
+    ffi (1.9.23)
+    ffi (1.9.23-x64-mingw32)
     forwardable-extended (2.6.0)
-    html-proofer (3.4.0)
-      activesupport (>= 4.2, < 6.0)
-      addressable (~> 2.3)
-      colored (~> 1.2)
-      mercenary (~> 0.3.2)
-      nokogiri (~> 1.5)
-      parallel (~> 1.3)
-      typhoeus (~> 0.7)
-      yell (~> 2.0)
-    i18n (0.8.1)
-    jekyll (3.4.0)
+    http_parser.rb (0.6.0)
+    i18n (0.9.5)
+      concurrent-ruby (~> 1.0)
+    jekyll (3.7.3)
       addressable (~> 2.4)
       colorator (~> 1.0)
+      em-websocket (~> 0.5)
+      i18n (~> 0.7)
       jekyll-sass-converter (~> 1.0)
-      jekyll-watch (~> 1.1)
-      kramdown (~> 1.3)
-      liquid (~> 3.0)
+      jekyll-watch (~> 2.0)
+      kramdown (~> 1.14)
+      liquid (~> 4.0)
       mercenary (~> 0.3.3)
       pathutil (~> 0.9)
-      rouge (~> 1.7)
+      rouge (>= 1.7, < 4)
       safe_yaml (~> 1.0)
-    jekyll-sass-converter (1.5.0)
+    jekyll-sass-converter (1.5.2)
       sass (~> 3.4)
-    jekyll-watch (1.5.0)
-      listen (~> 3.0, < 3.1)
-    kramdown (1.13.2)
-    liquid (3.0.6)
-    listen (3.0.8)
+    jekyll-watch (2.0.0)
+      listen (~> 3.0)
+    kramdown (1.16.2)
+    liquid (4.0.0)
+    listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
+      ruby_dep (~> 1.2)
     mercenary (0.3.6)
-    mini_portile2 (2.1.0)
-    minitest (5.10.1)
-    nokogiri (1.7.0.1)
-      mini_portile2 (~> 2.1.0)
-    nokogiri (1.7.0.1-x64-mingw32)
-      mini_portile2 (~> 2.1.0)
-    parallel (1.10.0)
-    pathutil (0.14.0)
+    pathutil (0.16.1)
       forwardable-extended (~> 2.6)
-    public_suffix (2.0.5)
-    rb-fsevent (0.9.8)
-    rb-inotify (0.9.8)
-      ffi (>= 0.5.0)
-    rouge (1.11.1)
+    public_suffix (3.0.2)
+    rb-fsevent (0.10.3)
+    rb-inotify (0.9.10)
+      ffi (>= 0.5.0, < 2)
+    rouge (3.1.1)
+    ruby_dep (1.5.0)
     safe_yaml (1.0.4)
-    sass (3.4.23)
-    thread_safe (0.3.6)
-    typhoeus (0.8.0)
-      ethon (>= 0.8.0)
-    tzinfo (1.2.2)
-      thread_safe (~> 0.1)
-    yell (2.0.7)
+    sass (3.5.6)
+      sass-listen (~> 4.0.0)
+    sass-listen (4.0.0)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
 
 PLATFORMS
   ruby
   x64-mingw32
 
 DEPENDENCIES
-  html-proofer
   jekyll
 
 BUNDLED WITH
-   1.15.4
+   1.16.0