diff --git a/Gemfile.lock b/Gemfile.lock
index 5eb22e3..c803c8a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -3,7 +3,7 @@ GEM
   specs:
     addressable (2.5.2)
       public_suffix (>= 2.0.2, < 4.0)
-    asciidoctor (1.5.7.1)
+    asciidoctor (2.0.18)
     colorator (1.1.0)
     concurrent-ruby (1.0.5)
     em-websocket (0.5.1)