Close "Needs Info" issues when inactive for long period of time

[aaronang]

Babelbot will wait for 30 days until closing the issue after an issue has been labeled "Needs Info". The setup is kind of troublesome though.

First, we have to generate a signature.

The hash has to be computed manually by using GITHUB_SECRET in Node CLI:

var crypto = require('crypto')

var body = {
  "action": "closing",
  "repository": {
    "owner": {
      "login": "babel"
    },
    "name": "babel"
  }
}

crypto
  .createHmac('sha1', GITHUB_SECRET)
  .update(new Buffer(JSON.stringify(body), 'utf-8'))
  .digest('hex');

// Output: HASH

Then, create a JSON object by replacing <HASH> with the generated hash:

{
  "signature": "sha1=<HASH>",
  "data": {
    "action": "closing",
    "repository": {
      "owner": {
        "login": "babel"
      },
      "name": "babel"
    }
  },
  "type": "issues"
}

This JSON object can then be send via a CloudWatch rule according to a schedule.

Fixes #20.