Cache Brew builds with travis ci : <p>I have a Travis CI <code>osx</code> build with a <code>brew</code> dependency that has to be built from source.</p>

<p>I know that Travis has the <code>cache</code> feature, but it doesn't have any documentation on how to cache <code>brew</code> builds or outputs.</p>

<p>Any idea on how to cache a <code>brew</code> package in travis?</p>
