Merge pull request #9061 from swagger-api/fix-ruby-test

fix travis ruby tests

.travis.yml

@@ -35,7 +35,9 @@ addons:
 
 before_install:
  # required when sudo: required for the Ruby petstore tests
- - gem install bundler
+ - gem install bundler -v '< 2'
+ - gem update --system 2.7.8
+ - gem --version
  - npm install -g typescript
  - npm install -g npm
  - npm config set registry http:https://registry.npmjs.org/