diff --git a/Gemfile.lock b/Gemfile.lock
index 4ca5fd5..c54fa5d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -16,7 +16,7 @@ GEM
     colorator (1.1.0)
     commonmarker (0.17.13)
       ruby-enum (~> 0.5)
-    concurrent-ruby (1.1.7)
+    concurrent-ruby (1.1.8)
     dnsruby (1.61.5)
       simpleidn (~> 0.1)
     em-websocket (0.5.2)
@@ -29,7 +29,7 @@ GEM
     faraday (1.1.0)
       multipart-post (>= 1.2, < 3)
       ruby2_keywords
-    ffi (1.13.1)
+    ffi (1.15.0)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
     github-pages (209)
@@ -194,12 +194,12 @@ GEM
       gemoji (~> 3.0)
       html-pipeline (~> 2.2)
       jekyll (>= 3.0, < 5.0)
-    kramdown (2.3.0)
+    kramdown (2.3.1)
       rexml
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
     liquid (4.0.3)
-    listen (3.2.1)
+    listen (3.5.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
@@ -221,7 +221,7 @@ GEM
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.4)
+    rexml (3.2.5)
     rouge (3.23.0)
     ruby-enum (0.8.0)
       i18n