Add workaround for ruby 2.5.5

Author: deivid-rodriguez

.travis.yml

@@ -2,6 +2,8 @@ before_install:
   - gem update --system 2.7.9
   - gem install bundler:1.17.3
   - rvm @global do gem uninstall did_you_mean
+  - # Travis's rvm 2.5.5 installation comes with bundler 2.0.1 for some reason.
+  - if [ "$TRAVIS_RUBY_VERSION" = "2.5.5" ]; then rvm @global do gem uninstall bundler -v 2.0.1 -x; fi
 bundler_args: --without development
 language: ruby
 rvm: