diff --git a/Gemfile.lock b/Gemfile.lock
index a349def0317..580e3c4816e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -259,6 +259,8 @@ GEM
     pry-byebug (3.9.0)
       byebug (~> 11.0)
       pry (~> 0.13.0)
+    psych (5.0.0)
+      stringio
     public_suffix (4.0.6)
     pwned (2.3.0)
     racc (1.6.0)
@@ -315,7 +317,8 @@ GEM
       ffi (>= 1.0.6)
       msgpack (>= 0.4.3)
       optimist (>= 3.0.0)
-    rdoc (6.3.3)
+    rdoc (6.5.0)
+      psych (>= 4.0.0)
     regexp_parser (2.2.0)
     request_store (1.5.0)
       rack (>= 1.4)
@@ -397,6 +400,7 @@ GEM
       activesupport (>= 5.2)
       sprockets (>= 3.0.0)
     statsd-instrument (2.3.5)
+    stringio (3.0.2)
     thor (1.1.0)
     tilt (2.0.10)
     toxiproxy (1.0.3)