chore(ci): bump Ruby versions

DirtyF · web-flow · commit 5ae016be5def · 2020-04-13T12:48:26.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,8 +1,8 @@
 language: ruby
 cache: bundler
 rvm:
-  - &latest_ruby 2.6
-  - 2.4
+  - &latest_ruby 2.7
+  - 2.5
 
 env:
   - JEKYLL_VERSION="~> 3.8"
