title: Can I pull a specific commit with composer?
body: <p>Is it possible to fetch a certain pull request with composer? Like a specific commit from a fork? What would the directive look like?</p>
  
  <p><strong>edit: context</strong> This would be helpful so I don't have to wait for a new tag to be created.
   I am certain it will be merged, however I don't know if when then devs will get a chance and I'd rather not put off the work flow I am in...</p>
  
  <p><strong>edit 2:</strong> now that I think about it, surely when developers make a fork of a public package they might need to test their own fork within a project or two before even pushing a pull request</p>
  
  <p><strong>edit 3: example</strong> I'm trying to pull this <a href="https://github.com/valorin/dispatcher/commit/c566eb6902f378abd59943e7ea09f61e734c8960" rel="noreferrer">https://github.com/valorin/dispatcher/commit/c566eb6902f378abd59943e7ea09f61e734c8960</a> to no avail, I tried:</p>
  
  <pre><code>    "valorin/dispatcher": "develop#c566eb6902f378abd59943e7ea09f61e734c8960"
  </code></pre>
  
  <p>and</p>
  
  <pre><code>    "indatus/dispatcher": "develop#c566eb6902f378abd59943e7ea09f61e734c8960"
  </code></pre>
  
  <p><strong>edit 4: great success</strong></p>
  
  <pre><code>"require": {
          "indatus/dispatcher": "dev-develop#c566eb6"
  }
  </code></pre>
  
  <p>adding the <code>dev-</code> prefix did the trick</p>