Update dependencies that don't work in ruby 2.4

Author: cibernox

Gemfile.lock

@@ -83,7 +83,7 @@ GEM
       gemoji (~> 2.0)
       html-pipeline (~> 1.9)
       jekyll (>= 2.0)
-    json (1.8.3)
+    json (1.8.6)
     kramdown (1.5.0)
     liquid (2.6.2)
     listen (2.10.1)
@@ -119,7 +119,7 @@ GEM
       parslet (~> 1.5.0)
     tzinfo (1.2.2)
       thread_safe (~> 0.1)
-    yajl-ruby (1.2.1)
+    yajl-ruby (1.2.2)
 
 PLATFORMS
   ruby
@@ -129,4 +129,4 @@ DEPENDENCIES
   jekyll
 
 BUNDLED WITH
-   1.13.6
+   1.13.7