Update gh-pages dependencies

In particular, this clears a security alert about the stale version of
nokogiri that was in the lockfile.

Author: fredemmott

docs/Gemfile.lock

@@ -13,12 +13,13 @@ GEM
       execjs
     coffee-script-source (1.12.2)
     colorator (1.1.0)
-    ethon (0.10.1)
+    concurrent-ruby (1.1.4)
+    ethon (0.12.0)
       ffi (>= 1.3.0)
     execjs (2.7.0)
-    faraday (0.10.1)
+    faraday (0.15.4)
       multipart-post (>= 1.2, < 3)
-    ffi (1.9.14)
+    ffi (1.10.0)
     forwardable-extended (2.6.0)
     gemoji (2.1.0)
     github-pages (104)
@@ -51,10 +52,11 @@ GEM
       octokit (~> 4.0)
       public_suffix (~> 1.4)
       typhoeus (~> 0.7)
-    html-pipeline (2.4.2)
+    html-pipeline (2.10.0)
       activesupport (>= 2)
       nokogiri (>= 1.4)
-    i18n (0.7.0)
+    i18n (0.9.5)
+      concurrent-ruby (~> 1.0)
     jekyll (3.3.0)
       addressable (~> 2.4)
       colorator (~> 1.0)
@@ -91,49 +93,53 @@ GEM
     jekyll-sitemap (0.12.0)
       jekyll (~> 3.3)
     jekyll-swiss (0.4.0)
-    jekyll-watch (1.5.0)
-      listen (~> 3.0, < 3.1)
+    jekyll-watch (1.5.1)
+      listen (~> 3.0)
     jemoji (0.7.0)
       activesupport (~> 4.0)
       gemoji (~> 2.0)
       html-pipeline (~> 2.2)
       jekyll (>= 3.0)
-    json (1.8.3)
+    json (1.8.6)
     kramdown (1.11.1)
     liquid (3.0.6)
     listen (3.0.6)
       rb-fsevent (>= 0.9.3)
       rb-inotify (>= 0.9.7)
     mercenary (0.3.6)
-    mini_portile2 (2.1.0)
+    mini_portile2 (2.4.0)
     minima (2.0.0)
-    minitest (5.10.1)
+    minitest (5.11.3)
     multipart-post (2.0.0)
-    net-dns (0.8.0)
-    nokogiri (1.7.0.1)
-      mini_portile2 (~> 2.1.0)
-    octokit (4.6.2)
+    net-dns (0.9.0)
+    nokogiri (1.10.1)
+      mini_portile2 (~> 2.4.0)
+    octokit (4.13.0)
       sawyer (~> 0.8.0, >= 0.5.3)
-    pathutil (0.14.0)
+    pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (1.5.3)
-    rb-fsevent (0.9.8)
-    rb-inotify (0.9.7)
-      ffi (>= 0.5.0)
+    rb-fsevent (0.10.3)
+    rb-inotify (0.10.0)
+      ffi (~> 1.0)
     rouge (1.11.1)
     safe_yaml (1.0.4)
-    sass (3.4.23)
+    sass (3.7.3)
+      sass-listen (~> 4.0.0)
+    sass-listen (4.0.0)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
     sawyer (0.8.1)
       addressable (>= 2.3.5, < 2.6)
       faraday (~> 0.8, < 1.0)
-    terminal-table (1.7.3)
-      unicode-display_width (~> 1.1.1)
-    thread_safe (0.3.5)
+    terminal-table (1.8.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
+    thread_safe (0.3.6)
     typhoeus (0.8.0)
       ethon (>= 0.8.0)
-    tzinfo (1.2.2)
+    tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    unicode-display_width (1.1.2)
+    unicode-display_width (1.4.1)
 
 PLATFORMS
   ruby
@@ -142,4 +148,4 @@ DEPENDENCIES
   github-pages (~> 104)
 
 BUNDLED WITH
-   1.13.1
+   1.16.1