diff --git a/ruby/Gemfile.lock b/ruby/Gemfile.lock
index 6b4862b..68971b9 100644
--- a/ruby/Gemfile.lock
+++ b/ruby/Gemfile.lock
@@ -18,7 +18,7 @@ GEM
       treetop (~> 1.6.0)
       ttfunk (~> 1.7.0)
     concurrent-ruby (1.3.6)
-    css_parser (1.21.1)
+    css_parser (1.22.0)
       addressable
     gmagick (0.0.3)
     hashery (2.1.2)