.travis.yml in zold-ruby-sdk-0.1.0 vs .travis.yml in zold-ruby-sdk-0.2.0

@@ -1,20 +1,16 @@
 language: ruby
 rvm:
-  - 2.3.1
-  - 2.3.3
-  - 2.4.5
+  - 2.6.0
 cache: bundler
 branches:
   only:
     - master
 install:
   - travis_retry bundle update
-  - gem install pdd
-  - sudo apt-get install cppcheck
+  - gem install pdd -v 0.20.5
 script:
   - pdd -f /dev/null
-  - cppcheck --enable=all --quiet --suppress=unusedFunction .
   - export RUBYOPT="-W0"
-  - rake --quiet
+  - bundle exec rake --quiet
 after_success:
   - "bash <(curl -s https://codecov.io/bash)"