title: how to force bower to install a certain version of dependency
body: <p>Assume a <code>bower.json</code> file in which dependencies are like</p>
  
  <pre><code>"dependencies": {
      "angular": "~1.5.x",
      "angular-routing": "*",
      "ngDialog": "*",
      "requirejs": "*"
  }
  </code></pre>
  
  <p>because  <code>angular-routing</code> requires another version of <code>angular</code> (say <code>1.2.x</code>), bower prompts me to choose a version.</p>
  
  <p>How could I force bower to install <code>angular ~1.5.x</code> automatically?</p>