title: Change only one route param
body: <p>Let's say I have a <code>Route</code> with three params, like so:</p>
  
  <pre><code>&lt;Route path="inbox/:filter/:middleFilter/:endFilter" component={Inbox}/&gt;
  </code></pre>
  
  <p><strong>Is there any way for me to just update one of those params at a time?</strong> For example, if the current URL is:</p>
  
  <pre><code>/inbox/asdf/1234/qwer
  </code></pre>
  
  <p>and I want to change the numbers <code>1234</code> (<code>middleFilter</code>), is there any React Router way of updating it? Something along the lines of:</p>
  
  <pre><code>history.push({
    params: {
      middleFilter: 6789
    }
  })
  </code></pre>