Feature Request: default jest configuration in package.json

[tanichols-zz]

Would it be possible to add a default jest configuration to the generated package.json? Something like the following:

"jest": {
  "collectCoverageFrom": [
    "src/**/*.{js,jsx}",
    "!src/registerServiceWorker.js",
    "!src/index.js"
  ],
  "coverageThreshold": {
    "global": {
      "branches": 80,
      "functions": 80,
      "lines": 80,
      "statements": -10
    }
  }
}

As I see it, this would make it easily discoverable that the default setup supports a jest configuration in package.json.

[bugzpodder]

I don't feel strongly about implementing this. Documenting jest is what the User Guide is for. Also, these defaults are not sensible especially considering the number of react apps. For some users they just want to get start to build things without worrying about total coverage.