diff --git a/Gemfile.lock b/Gemfile.lock
index edbcdeceba4..749ae5821c8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -399,7 +399,7 @@ GEM
       msgpack (>= 0.4.3)
       optimist (>= 3.0.0)
     rchardet (1.8.0)
-    rdoc (6.7.0)
+    rdoc (6.8.1)
       psych (>= 4.0.0)
     redcarpet (3.6.0)
     redis (4.8.1)