title: Plotly : Heatmap color legend i subplot
body: <p>I'm working in python with plotly, trying to have two heatmap subplot with a custom legend for each.
  But here what I see with the following code :</p>
  <pre><code>import plotly
  
  
  fig = plotly.subplots.make_subplots(rows=2, cols=1)
  
  mat = np.array([[1,0],
                  [0,1]])
  
  
  fig.add_trace(go.Heatmap(z=mat, colorscale='Bluered_r'), row=1, col=1)
  
  fig.add_trace(go.Heatmap(z=mat*10, colorscale='Bluered_r'), row=2, col=1)
  
  fig.show()
  </code></pre>
  <p><a href="https://i.stack.imgur.com/1AGvG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1AGvG.png" alt="enter image description here" /></a></p>
  <p>you can see that both legend are displayed at the same place.</p>
  <p>Thanks for your help!</p>