.travis.yml in stellar_client-0.6.1 vs .travis.yml in stellar_client-0.7.0

@@ -1,8 +1,8 @@
 sudo: false
 language: ruby
 cache: bundler
 rvm:
-  - 2.5.1
-before_install: gem install bundler -v 1.16.2
+  - 2.6.3
+before_install: gem install bundler -v 1.16.6
 before_script:
   - cp spec/config.yml{.sample,}