title: Get Cargo.toml version at runtime
body: <p>In my <code>Cargo.toml</code> I have this block</p>
  
  <pre><code>[package]
  name = "packagename"
  version = "0.1.0"
  authors = ["me &lt;abuse@gmail.com&gt;"]
  </code></pre>
  
  <p>How can I fetch what [package].version is at runtime?</p>