title: How to get composer to update version numbers to the latest ones available in composer.json?
body: <p>In my <code>composer.json</code> config file, I have: </p>
  
  <pre><code>"require": {
      "zendframework/zend-log" : "~2.3",
   },
  "require-dev": {
      "phpunit/phpunit": "^5.4"
   } 
  </code></pre>
  
  <p>I want:</p>
  
  <pre><code>"require": {
     "zendframework/zend-log" : "^2.9",
  },
  "require-dev": {
      "phpunit/phpunit": "^6.2"
   } 
  </code></pre>
  
  <p>Note the version number changes</p>
  
  <p>How?  I want it to be done automatically without me having to look up each individual latest version that's available and edit it manually.</p>
  
  <p>There is this question but it does not help: <a href="https://stackoverflow.com/questions/14302326/how-can-i-make-the-composer-to-get-the-latest-version-in-composer-json">How to resolve package not found error when trying to make the composer get the latest package versions?</a></p>