diff --git a/docs/Gemfile.lock b/docs/Gemfile.lock
index 7c1808a..b40ee07 100644
--- a/docs/Gemfile.lock
+++ b/docs/Gemfile.lock
@@ -165,7 +165,7 @@ GEM
     minitest (5.10.1)
     multipart-post (2.0.0)
     net-dns (0.8.0)
-    nokogiri (1.7.0.1)
+    nokogiri (~> 1.8.1)
       mini_portile2 (~> 2.1.0)
     octokit (4.6.2)
       sawyer (~> 0.8.0, >= 0.5.3)