.travis.yml in ietfbib-0.4.5 vs .travis.yml in ietfbib-0.4.6

@@ -1,14 +1,15 @@
-sudo: false
 language: ruby
-
+os:
+- linux
+- osx
 rvm:
-  - 2.5
-  - 2.4
-  - 2.3
-  - ruby-head
-
-before_install: gem install bundler -v 1.16.1
-
+- 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
+    - rvm: ruby-head
\ No newline at end of file