message: fix npm run command
  Add --mode development option in webpack
  change path of index.js in help command
diff: "lint": "eslint --fix **/*.ts",
  "demo": "node dist/index.js --demo --type-name DemoFields -o demo-fields.d.ts",
  "generate": "node dist/index.js --host https://****.cybozu.com --username *** --password *** --app-id ***",
  - "help": "node index.js --help",
  + "help": "node dist/index.js --help",
  "test": "jest",
  "prettier:base": "prettier --parser typescript",
  "prettier:check": "npm run prettier:base -- --list-different \"src/**/*.{ts,tsx}\"",
  "prettier:write": "npm run prettier:base -- --write \"src/**/*.{ts,tsx}\"",
  - "build:integration": "webpack --config webpack.config.js"
  + "build:integration": "webpack --mode development --config webpack.config.js"
  },
  "author": "Tomoya Yokota",
  "license": "MIT",
  