diff --git a/Gemfile.lock b/Gemfile.lock
index ab9255b..ded14a0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -79,7 +79,7 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
-    rdoc (6.0.3)
+    rdoc (6.3.1)
     rspec (3.7.0)
       rspec-core (~> 3.7.0)
       rspec-expectations (~> 3.7.0)