.travis.yml in left_joins-1.0.4 vs .travis.yml in left_joins-1.0.5

@@ -2,12 +2,12 @@
 rvm:
   - 2.2
   - 2.3
 sudo: required
 dist: trusty
-before_install: 
-  - gem install bundler
-  - gem update --system
+before_install:
+  - gem i rubygems-update -v '<3' && update_rubygems
+  - gem install bundler -v 1.17.3
   - gem --version
 gemfile:
   - gemfiles/3.2.gemfile
   - gemfiles/4.0.gemfile
   - gemfiles/4.2.gemfile