.travis.yml in r10k-2.5.5 vs .travis.yml in r10k-2.6.0

@@ -3,9 +3,10 @@
 bundler_args: "--without system"
 script: "bundle exec rspec --color --format documentation spec/unit"
 notifications:
   email: false
 sudo: false
+before_install: gem update bundler
 rvm:
   - "2.3.0"
   - "2.2.0"
   - "2.1.0"
   - "2.0.0"