diff --git a/Gemfile.lock b/Gemfile.lock
index c8135ce..2f1e5ff 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -40,7 +40,8 @@ GEM
     regexp_parser (2.9.0)
     reverse_markdown (2.1.1)
       nokogiri
-    rexml (3.2.6)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
       rspec-expectations (~> 3.9.0)
@@ -96,6 +97,7 @@ GEM
       thor (~> 1.0)
       tilt (~> 2.0)
       yard (~> 0.9, >= 0.9.24)
+    strscan (3.1.0)
     thor (1.3.0)
     tilt (2.3.0)
     unicode-display_width (2.5.0)