.travis.yml in linkedin_sign_in-0.3.1 vs .travis.yml in linkedin_sign_in-0.4.0

@@ -1,16 +1,16 @@
 language: ruby
 sudo: false
 cache: bundler
 
-# Bundler/RubyGems incompat on Ruby 2.5.0
-before_install: gem install bundler
+# Bundler/RubyGems incompat on Ruby 2.5.0 and 2.6.1
+before_install: gem update --system && gem install bundler -v 1.17.3
 
 rvm:
-  - 2.2
   - 2.3
   - 2.4
   - 2.5
+  - 2.6
   - ruby-head
 
 matrix:
   allow_failures:
     - rvm: ruby-head