Update Jekyll to v3.6.0. (#24102)

Gemfile

@@ -1,7 +1,7 @@
 source 'https://rubygems.org'
 
 group :development, :test do
-  gem 'jekyll', '~> 3.5.1'
+  gem 'jekyll', '~> 3.6.0'
   gem 'jekyll-redirect-from', '~> 0.12.1'
   gem 'jekyll-sitemap', '~> 1.1.1'
   gem 'jekyll-toc', '~> 0.3.0'

Gemfile.lock

@@ -7,16 +7,16 @@ GEM
     ffi (1.9.18)
     ffi (1.9.18-x64-mingw32)
     forwardable-extended (2.6.0)
-    jekyll (3.5.2)
+    jekyll (3.6.0)
       addressable (~> 2.4)
       colorator (~> 1.0)
       jekyll-sass-converter (~> 1.0)
       jekyll-watch (~> 1.1)
-      kramdown (~> 1.3)
+      kramdown (~> 1.14)
       liquid (~> 4.0)
       mercenary (~> 0.3.3)
       pathutil (~> 0.9)
-      rouge (~> 1.7)
+      rouge (>= 1.7, < 3)
       safe_yaml (~> 1.0)
     jekyll-redirect-from (0.12.1)
       jekyll (~> 3.3)
@@ -34,11 +34,11 @@ GEM
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
     mercenary (0.3.6)
-    mini_portile2 (2.2.0)
-    nokogiri (1.8.0)
-      mini_portile2 (~> 2.2.0)
-    nokogiri (1.8.0-x64-mingw32)
-      mini_portile2 (~> 2.2.0)
+    mini_portile2 (2.3.0)
+    nokogiri (1.8.1)
+      mini_portile2 (~> 2.3.0)
+    nokogiri (1.8.1-x64-mingw32)
+      mini_portile2 (~> 2.3.0)
     pathutil (0.14.0)
       forwardable-extended (~> 2.6)
     public_suffix (3.0.0)
@@ -46,7 +46,7 @@ GEM
     rb-fsevent (0.10.2)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
-    rouge (1.11.1)
+    rouge (2.2.1)
     safe_yaml (1.0.4)
     sass (3.4.25)
     scss_lint (0.54.0)
@@ -58,7 +58,7 @@ PLATFORMS
   x64-mingw32
 
 DEPENDENCIES
-  jekyll (~> 3.5.1)
+  jekyll (~> 3.6.0)
   jekyll-redirect-from (~> 0.12.1)
   jekyll-sitemap (~> 1.1.1)
   jekyll-toc (~> 0.3.0)