diff --git a/docs/Gemfile.lock b/docs/Gemfile.lock
index 893479d..af1d0c1 100644
--- a/docs/Gemfile.lock
+++ b/docs/Gemfile.lock
@@ -6,8 +6,8 @@ GEM
       minitest (~> 5.1)
       thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
-    addressable (2.7.0)
-      public_suffix (>= 2.0.2, < 5.0)
+    addressable (2.8.1)
+      public_suffix (>= 2.0.2, < 6.0)
     bibtex-ruby (4.4.7)
       latex-decode (~> 0.0)
     citeproc (1.0.9)