title: How to set Axis step in Google Chart?
body: <p>I'm wondering how to set axis step in a google chart built from JavaScript?
  I use this to set min and max:</p>
  
  <pre><code>vAxis: {
  title: 'temps (ms)',
      viewWindowMode: 'explicit',
      viewWindow: {
          max: 180,
          min: 0
      },
  }
  </code></pre>
  
  <p>And I need to add an other constraint to fix vertical step to 0.1 for example.</p>