.travis.yml in omml2mathml-0.0.4 vs .travis.yml in omml2mathml-0.0.5

@@ -1,17 +1,17 @@
-dist: trusty
 language: ruby
-sudo: false
-
-before_install:
-  - gem install bundler -v 2.0.1
-
+cache: bundler
+os:
+- linux
+- osx
 rvm:
-  - 2.5
-  - 2.4
-  - 2.3
-  - ruby-head
-
+- 2.5
+- 2.4
+- 2.3
+- ruby-head
+before_install:
+- gem install bundler -v 2.0.1
+- bundle update
 matrix:
   allow_failures:
     - rvm: ruby-head