title: Explicitly set colours of the boxplot in ploltly
body: <p>I am using <code>plotly express</code> to plot <code>boxplot</code> as shown below:</p>
  
  <pre><code>px.box(data_frame=df, 
         y="price", 
         x="products",
         points="all")
  </code></pre>
  
  <p>However, the boxpots of the products shown up with the same colours. They are four products. I would like to colour each with a different colour, using an additional paramter <code>color_discrete_sequence</code> does not work.</p>