diff --git a/Gemfile.lock b/Gemfile.lock
index f9b4eb1..c6e5d61 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,7 +6,7 @@ GEM
       ffi-rzmq-core (>= 1.0.7)
     ffi-rzmq-core (1.0.7)
       ffi
-    zlib (1.1.0)
+    zlib (3.0.1)
 
 PLATFORMS
   x86_64-darwin-19