Connector engines definition and CircleCI configuration

new-node8-.circleci-config.yml

# Javascript Node CircleCI 2.0 configuration file
#
# Check https://circleci.com/docs/2.0/language-javascript/ for more details
#
version: 2
jobs:
  build:
    docker:
      - image: circleci/node:8.9
    working_directory: ~/repo

    steps:
      - checkout

      # Download and cache dependencies
      - restore_cache:
          keys:
          - v1-dependencies-{{ checksum "package.json" }}
          # fallback to using the latest cache if no exact match is found
          - v1-dependencies-

      - run: yarn install

      - save_cache:
          paths:
            - node_modules
          key: v1-dependencies-{{ checksum "package.json" }}

      # run tests!
      - run: yarn test
      - run: ./node_modules/.bin/hull-connector-tester

new-node8-package.json

{
  "engines": {
    "node": "8.11.x",
    "npm": "5.5.x",
    "yarn": "^1.6.x"
  }
}