feat(jekyll): update support for v3.4.0

Gemfile

@@ -1,7 +1,7 @@
 source 'https://rubygems.org'
 
 group :development do
-  gem 'jekyll', '3.3.0'
+  gem 'jekyll', '3.4.0'
   gem 'jekyll-last-modified-at'
   gem 'match_regex'
   gem 'stringex'

Gemfile.lock

@@ -4,9 +4,9 @@ GEM
     addressable (2.5.0)
       public_suffix (~> 2.0, >= 2.0.2)
     colorator (1.1.0)
-    ffi (1.9.14)
+    ffi (1.9.17)
     forwardable-extended (2.6.0)
-    jekyll (3.3.0)
+    jekyll (3.4.0)
       addressable (~> 2.4)
       colorator (~> 1.0)
       jekyll-sass-converter (~> 1.0)
@@ -19,11 +19,11 @@ GEM
       safe_yaml (~> 1.0)
     jekyll-last-modified-at (0.3.4)
       jekyll
-    jekyll-sass-converter (1.4.0)
+    jekyll-sass-converter (1.5.0)
       sass (~> 3.4)
     jekyll-watch (1.5.0)
       listen (~> 3.0, < 3.1)
-    kramdown (1.12.0)
+    kramdown (1.13.2)
     liquid (3.0.6)
     listen (3.0.8)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -32,23 +32,23 @@ GEM
     mercenary (0.3.6)
     pathutil (0.14.0)
       forwardable-extended (~> 2.6)
-    public_suffix (2.0.4)
+    public_suffix (2.0.5)
     rb-fsevent (0.9.8)
-    rb-inotify (0.9.7)
+    rb-inotify (0.9.8)
       ffi (>= 0.5.0)
     rouge (1.11.1)
     safe_yaml (1.0.4)
-    sass (3.4.22)
-    stringex (2.6.1)
+    sass (3.4.23)
+    stringex (2.7.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  jekyll (= 3.3.0)
+  jekyll (= 3.4.0)
   jekyll-last-modified-at
   match_regex
   stringex
 
 BUNDLED WITH
-   1.13.6
+   1.13.7