diff --git a/Gemfile.lock b/Gemfile.lock
index 734a888..7f49a8a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -8,7 +8,7 @@ GEM
       tzinfo (~> 2.0)
     addressable (2.8.1)
       public_suffix (>= 2.0.2, < 6.0)
-    async (2.4.2)
+    async (2.5.0)
       console (~> 1.10)
       io-event (~> 1.1)
       timers (~> 4.1)