language: ruby
rvm:
  - 2.4.6
  - 2.5.5
  - 2.6.3
  - ruby-head
matrix:
  allow_failures:
    - rvm: ruby-head
script:
  - bundle exec rake ci

language: ruby
rvm:
  - 2.4
  - 2.5
  - 2.6
  - ruby-head
matrix:
  allow_failures:
    - rvm: ruby-head
script:
  - bundle exec rake ci

Use two-part version numbers for rvm
CI: Use two-part version numbers for rvm