.travis.yml in jekyll-feed-0.12.0 vs .travis.yml in jekyll-feed-0.12.1

@@ -1,13 +1,21 @@
 language: ruby
 cache: bundler
-sudo: false
 rvm:
-- 2.6
-- 2.4
+  - &latest_ruby 2.6
+  - 2.4
+  - 2.3
 env:
   global:
-  - NOKOGIRI_USE_SYSTEM_LIBRARIES=true
+    - NOKOGIRI_USE_SYSTEM_LIBRARIES=true
+  matrix:
+    - JEKYLL_VERSION="~> 3.8"
+matrix:
+  include:
+    - rvm: *latest_ruby
+      env: JEKYLL_VERSION="~> 3.7.4"
+    - rvm: *latest_ruby
+      env: JEKYLL_VERSION=">= 4.0.0.pre.alpha1"
 before_install:
 - gem update --system
 - gem install bundler
 before_script: bundle update
 script: script/cibuild