diff --git a/Gemfile.lock b/Gemfile.lock
index 99fa714..93c7d75 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -3,7 +3,7 @@ GEM
   specs:
     addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
-    asciidoctor (1.5.6.1)
+    asciidoctor (2.0.18)
     colorator (1.1.0)
     ffi (1.15.3)
     forwardable-extended (2.6.0)