Bundler 2.x requires Ruby 2.3.0 and above.
For Ruby builds using Ruby < 2.3.0, we now execute
gem install bundler -v '< 2'
to ensure that a compatible version of Bundler is available.
Do keep in mind that, for builds in other languages, the user is responsible for installing a compatible version of Bundler, if it is not available. For example:
before_install: - rvm use 2.2.10 --install --binary --fuzzy - gem install bundler -v '< 2'