diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f9cca5b785..808f492a7d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -8,7 +8,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.5.8
+          ruby-version: 2.6.9
           bundler-cache: true
       - name: Set up coursier
         uses: coursier/setup-action@v1.2.0-M2
diff --git a/Dockerfile b/Dockerfile
index b972fe1c24..2fe3d70737 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:2.5
+FROM ruby:2.6
 
 RUN gem install bundler jekyll
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 0bbe4414f9..5b52d7697a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -54,9 +54,9 @@ GEM
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
-    mini_portile2 (2.6.1)
-    nokogiri (1.12.5)
-      mini_portile2 (~> 2.6.1)
+    mini_portile2 (2.8.0)
+    nokogiri (1.13.3)
+      mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     nokogumbo (2.0.2)
       nokogiri (~> 1.8, >= 1.8.4)
@@ -64,7 +64,7 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.6)
-    racc (1.5.2)
+    racc (1.6.0)
     rainbow (3.0.0)
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)