diff --git a/Gemfile.lock b/Gemfile.lock
index ce53fb0..5a641cb 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -40,7 +40,7 @@ GEM
     psych (5.1.2)
       stringio
     rake (13.1.0)
-    rdoc (6.6.2)
+    rdoc (6.6.3.1)
       psych (>= 4.0.0)
     reline (0.4.2)
       io-console (~> 0.5)