diff --git a/Gemfile.lock b/Gemfile.lock
index 5ab9943..8d1cbc2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -47,7 +47,7 @@ GEM
     public_suffix (4.0.1)
     rack (2.2.3)
     rake (13.0.1)
-    rdoc (6.2.0)
+    rdoc (6.3.2)
     rmagick (4.0.0)
     ruby-vips (2.0.17)
       ffi (~> 1.9)