.travis.yml in jekyll-feed-0.9.2 vs .travis.yml in jekyll-feed-0.9.3

@@ -1,14 +1,19 @@
 language: ruby
+cache: bundler
+sudo: false
 rvm:
+- 2.5
+- 2.4
+- 2.3
 - 2.2
 env:
   global:
   - NOKOGIRI_USE_SYSTEM_LIBRARIES=true
-cache: bundler
-sudo: false
+before_install:
+- gem update --system
 before_script: bundle update
-script: "./script/cibuild"
+script: script/cibuild
 notifications:
   email: false
 deploy:
   provider: rubygems
   api_key: