.travis.yml in pesapal-1.8.0 vs .travis.yml in pesapal-2.0.0

@@ -1,10 +1,12 @@
 language: ruby
 before_install:
   - gem update --system
   - gem install bundler
 rvm:
-  - 2.3
-  - 2.2
-  - 2.1
-  - 2.0
+  - '2.4.0'
+  - '2.3.3'
+  - '2.2.6'
+  - '2.1.9'
+  - '2.0.0-p648'
 script: bundle exec rspec spec
+sudo: false