title: NPM says peer dependency missing but packages are installed
body: <p>I am trying to install a Strapi project. After running npm install I get the following peer dependency warnings:</p>
  
  <pre><code>npm WARN eslint-config-airbnb@13.0.0 requires a peer of eslint@^3.9.1 but none is installed. You must install peer dependencies yourself.
  npm WARN eslint-config-airbnb@13.0.0 requires a peer of eslint-plugin-jsx-a11y@^2.2.3 but none is installed. You must install peer dependencies yourself.
  npm WARN eslint-config-airbnb@13.0.0 requires a peer of eslint-plugin-react@^6.6.0 but none is installed. You must install peer dependencies yourself.
  npm WARN eslint-config-airbnb-base@10.0.1 requires a peer of eslint@^3.9.1 but none is installed. You must install peer dependencies yourself.
  npm WARN react-ga@2.5.6 requires a peer of prop-types@^15.6.0 but none is installed. You must install peer dependencies yourself.
  npm WARN react-ga@2.5.6 requires a peer of react@^15.6.2 || ^16.0 but none is installed. You must install peer dependencies yourself.
  </code></pre>
  
  <p>However, when I check the installed version of these packages everything seems fine. For example:</p>
  
  <pre><code>$ npm view eslint version
  5.9.0
  $ npm view prop-types version
  15.6.2
  </code></pre>
  
  <p>This is from the Strapi-generated package.json (dependencies for prop-types and react I added)</p>
  
  <pre><code>"devDependencies": {
      "babel-eslint": "^7.1.1",
      "eslint": "^4.19.1",
      "eslint-config-airbnb": "^13.0.0",
      "eslint-plugin-import": "^2.11.0",
      "eslint-plugin-react": "^7.7.0"
    },
    "dependencies": {
      "lodash": "^4.17.5",
      "strapi": "3.0.0-alpha.15",
      "strapi-utils": "3.0.0-alpha.15",
      "strapi-hook-mongoose": "3.0.0-alpha.15",
      "prop-types": "^15.6.0",
      "react": "^15.6.2"
    },
  </code></pre>
  
  <p>Does this have to do with locally vs globally installed packages? Any help super appreciated!</p>