message: Add cross-env to test tasks
diff: "scripts": {
  "test": "npm run test:moment && npm run test:date-fns",
  "all-tests": "jest && npm run typescript",
  - "test:moment": "UTILS=moment && npm run all-tests",
  - "test:date-fns": "UTILS=date-fns && npm run all-tests",
  + "test:moment": "cross-env UTILS=moment && npm run all-tests",
  + "test:date-fns": "cross-env UTILS=date-fns && npm run all-tests",
  + "test:luxon": "cross-env UTILS=luxon && npm run all-tests",
  "typescript": "tsc -p tsconfig.json",
  "start": "cross-env NODE_ENV=development rollup --config --watch",
  "prebuild": "rimraf build",
  