.travis.yml in rasn1-0.6.8 vs .travis.yml in rasn1-0.7.0

@@ -1,9 +1,10 @@
 language: ruby
 rvm:
   - 2.3
   - 2.4
   - 2.5
+  - 2.6
 install:
-  - bundle install --path vendor/bundle --jobs=3 --retry=3
-script:
-  - bundle exec rake
+  - gem install bundler --version "~> 1.17.3"
+  - bundle _1.17.3_ install --path vendor/bundle --jobs=3 --retry=3
+