diff --git a/Gemfile.lock b/Gemfile.lock
index 3c5aa68..2a98d61 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -12,11 +12,11 @@ GEM
       minitest (>= 5.1)
       tzinfo (~> 2.0)
       zeitwerk (~> 2.3)
-    addressable (2.7.0)
-      public_suffix (>= 2.0.2, < 5.0)
+    addressable (2.8.1)
+      public_suffix (>= 2.0.2, < 6.0)
     amazing_print (1.3.0)
     coderay (1.1.3)
-    concurrent-ruby (1.1.8)
+    concurrent-ruby (1.1.10)
     crack (0.4.5)
       rexml
     deep_merge (1.2.1)
@@ -28,8 +28,6 @@ GEM
       scanf (~> 1.0)
       sxp (~> 1.1)
       unicode-types (~> 1.6)
-    hamster (3.0.0)
-      concurrent-ruby (~> 1.0)
     hashdiff (1.0.1)
     htmlentities (4.3.4)
     i18n (1.8.10)
@@ -46,10 +44,9 @@ GEM
     pry (0.14.1)
       coderay (~> 1.1)
       method_source (~> 1.0)
-    public_suffix (4.0.6)
+    public_suffix (5.0.0)
     racc (1.5.2)
-    rdf (3.1.14)
-      hamster (~> 3.0)
+    rdf (3.2.9)
       link_header (~> 0.0, >= 0.0.8)
     rdf-turtle (3.1.3)
       ebnf (~> 2.1)