title: Eslint gives error: Configuration for rule "strict" is invalid: Value "error" is the wrong type
body: <p>I tried to use Eslint with the following option:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>{
    "rules": {
      "indent": [
        2,
        2,
        {
          "SwitchCase": 1
        }
      ],
      "space-before-function-paren": [
        2,
        {
          "anonymous": "always",
          "named": "never"
        }
      ],
      "no-use-before-define": [
        2,
        "nofunc"
      ],
      // TODO: turn on later
      "comma-dangle": [
        0
      ],
      "prefer-template": 0
    },
    "env": {
      "node": true,
      "mocha": true
    },
    "extends": [
      "eslint:recommended",
      "airbnb/base"
    ]
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>And I am getting the error:  </p>
  
  <p>Error: ... ... /node_modules/eslint-config-airbnb-base/index.js:
      Configuration for rule "strict" is invalid:
      Value "error" is the wrong type.</p>
  
  <p>Referenced from: airbnb/base</p>
  
  <p>I think that this value: 'error' is causing the error.   </p>
  
  <p><strong>eslint-config-airbnb-base/rules/strict.js</strong>
  <div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>module.exports = {
    rules: {
      // babel inserts `'use strict';` for us
      strict: ['error', 'never']
    }
  };</code></pre>
  </div>
  </div>
  </p>
  
  <p>How can I resolve this error?</p>