diff --git a/docs/Gemfile.lock b/docs/Gemfile.lock
index d5eadbe..0ef6116 100644
--- a/docs/Gemfile.lock
+++ b/docs/Gemfile.lock
@@ -5,7 +5,7 @@ GEM
       public_suffix (>= 2.0.2, < 8.0)
     cgi (0.5.1)
     colorator (1.1.0)
-    concurrent-ruby (1.2.3)
+    concurrent-ruby (1.3.7)
     digest (3.2.0)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)