.travis.yml in iso-bib-item-0.4.4 vs .travis.yml in iso-bib-item-0.4.5

@@ -5,10 +5,10 @@
   - 2.5
   - 2.4
   - 2.3
   - ruby-head
 
-before_install: gem install bundler -v 1.16.1
+before_install: gem install bundler -v 2.0.1
 
 matrix:
   allow_failures:
-    - rvm: ruby-head
\ No newline at end of file
+    - rvm: ruby-head