message: webpack-plugin: add cjs to published output
  fix peer dependency version
diff: "prepack": "yarn build"
  },
  "peerDependencies": {
  - "@stylable/core": "^1.0.0",
  + "@stylable/core": "^2.0.0",
  "webpack": "^4.6.0"
  },
  "dependencies": {
  "webpack-sources": "^1.3.0"
  },
  "files": [
  + "cjs",
  "src",
  "!src/tsconfig.json"
  ],
  