diff --git a/sub-project/Gemfile.lock b/sub-project/Gemfile.lock
index 459cea7d..3c26e1fc 100644
--- a/sub-project/Gemfile.lock
+++ b/sub-project/Gemfile.lock
@@ -96,7 +96,7 @@ GEM
     rainbow (3.0.0)
     rake (13.0.1)
     rchardet (1.8.0)
-    rdoc (6.2.1)
+    rdoc (6.3.1)
     redis (4.2.2)
     regexp_parser (1.8.2)
     rexml (3.2.4)