title: composer - install new package without updating other packages
body: <p>I added a package in the <code>require</code> block of my <code>composer.json</code>.</p>
  
  <p>I do a <code>composer install</code> and it says <code>Nothing to install or update.</code></p>
  
  <p>In my understanding, <code>composer update</code> would work but I shouldn't do that because it updates the versions of the other packages to the latest, but I haven't tested my code on them.</p>
  
  <p>How do I install that new package?</p>