Update Gemfile.lock

To address security issues.

Author: matz

Gemfile.lock

@@ -20,8 +20,7 @@ GEM
     execjs (2.7.0)
     faraday (0.11.0)
       multipart-post (>= 1.2, < 3)
-    ffi (1.9.17)
-    ffi (1.9.17-x86-mingw32)
+    ffi (>= 1.9.17)
     forwardable-extended (2.6.0)
     gemoji (2.1.0)
     git (1.3.0)
@@ -76,7 +75,7 @@ GEM
       typhoeus (~> 0.7)
     html-pipeline (2.5.0)
       activesupport (>= 2)
-      nokogiri (~> 1.8.1)
+      nokogiri (>= 1.8.2)
     i18n (0.7.0)
     jekyll (3.3.1)
       addressable (~> 2.4)