diff --git a/Gemfile.lock b/Gemfile.lock
index 399bad1..7a45c14 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -90,11 +90,9 @@ GEM
       tilt (>= 1.3, < 3)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
-    thread_safe (0.3.6)
-    thread_safe (0.3.6-java)
     tilt (2.0.10)
-    tzinfo (1.2.5)
-      thread_safe (~> 0.1)
+    tzinfo (2.0.5)
+      concurrent-ruby (~> 1.0)
     tzinfo-data (1.2018.5)
       tzinfo (>= 1.0.0)
     unicode-display_width (1.7.0)