machine:
  environment:
    PATH: "${PATH}:${HOME}/.yarn/bin"
  node:
    version: node

dependencies:
  cache_directories:
    - ~/.yarn
    - ~/.cache/yarn
  pre:
    - ./yarn.sh -v 0.18.1
  override:
    - yarn --pure-lockfile
  post:
    - yarn run build

test:
  pre:
    - yarn run flow -- check
  override:
    - yarn test

machine:
  environment:
    PATH: "${PATH}:${HOME}/.yarn/bin"
  node:
    version: node

dependencies:
  cache_directories:
    - ~/.yarn
    - ~/.cache/yarn
  pre:
    - ./yarn.sh -v 0.23.0
  override:
    - yarn --pure-lockfile
  post:
    - yarn run build

test:
  pre:
    - yarn run flow -- check
  override:
    - yarn test

Upgrade Yarn in CI to 0.23.0
[CI] Upgrade Yarn in CI to 0.23.0
