diff --git a/Gemfile.lock b/Gemfile.lock
index 3a225c1..54dd2f6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -13,7 +13,7 @@ GEM
       concurrent-ruby (~> 1.0)
     minitest (5.11.3)
     puma (3.12.1)
-    rack (2.0.7)
+    rack (2.1.4)
     rspec (3.1.0)
       rspec-core (~> 3.1.0)
       rspec-expectations (~> 3.1.0)