diff --git a/Gemfile.lock b/Gemfile.lock
index 70ce018..b977149 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -842,7 +842,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.0.3)
-    puma (3.12.6)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)