language: ruby
rvm:
  - 2.1
  - 2.2
  - 2.3
  - 2.4
  - 2.5
  - 2.6

before_install:
  # This is a workaround for a problem with a specific version of bundler and
  # rubygems
  - gem update --system

language: ruby
rvm:
  - 2.2
  - 2.3
  - 2.4
  - 2.5
  - 2.6

before_install:
  # This is a workaround for a problem with a specific version of bundler and
  # rubygems
  - gem update --system

Remove testing for Ruby 2.1
Remove testing for Ruby 2.1

I need to run gem update --system in order to fix a compatibility
issue between ruby gems and bundler on Runy 2.5. However, this command
fails on Ruby 2.1, given that version 2.1 was EOL'd two years ago
this should be a safe change to make.
