diff --git a/images/Gemfile.lock b/images/Gemfile.lock
index d3a490a..b78db95 100644
--- a/images/Gemfile.lock
+++ b/images/Gemfile.lock
@@ -81,13 +81,14 @@ GEM
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2019.1009)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.8.0)
     minitest (5.11.3)
     multi_json (1.14.1)
     multi_xml (0.6.0)
     multipart-post (2.1.1)
-    nokogiri (1.10.8)
-      mini_portile2 (~> 2.4.0)
+    nokogiri (1.13.6)
+      mini_portile2 (~> 2.8.0)
+      racc (~> 1.4)
     open_uri_redirections (0.2.1)
     os (1.0.1)
     parallel (1.17.0)
@@ -97,6 +98,7 @@ GEM
       png_quantizator
     png_quantizator (0.2.1)
     public_suffix (4.0.3)
+    racc (1.6.0)
     representable (3.0.4)
       declarative (< 0.1.0)
       declarative-option (< 0.2.0)
@@ -123,7 +125,6 @@ GEM
       faraday (~> 0.9)
       jwt (>= 1.5, < 3.0)
       multi_json (~> 1.10)
-    slack-notifier (2.3.2)
     thread_safe (0.3.6)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
@@ -156,7 +157,6 @@ DEPENDENCIES
   piet
   rmagick
   rspec
-  slack-notifier
   vcr
   webmock