diff --git a/Gemfile.lock b/Gemfile.lock
index a2372e0..5d437e9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    asciidoctor (1.5.6.1)
+    asciidoctor (2.0.18)
     coderay (1.1.2)
     colorator (0.1)
     ffi (1.9.18)