title: Multiple axes labelling in R Plotly
body: <p>I am trying to make a dual axis plot using <code>plotly</code> in R. However, I am unable to name the first y-axis using the following code whicI i found here: <a href="https://plot.ly/r/multiple-axes/" rel="nofollow noreferrer">https://plot.ly/r/multiple-axes/</a></p>
  
  <pre><code>    library(plotly)
      ay &lt;- list(
      tickfont = list(color = "red"),
      overlaying = "y",
      side = "right",
      title = "second y axis"
      )
      p &lt;- plot_ly() %&gt;%
      add_lines(x = ~1:3, y = ~10*(1:3), name = "slope of 10") %&gt;%
      add_lines(x = ~2:4, y = ~1:3, name = "slope of 1", yaxis = "y2") %&gt;%
      layout(
      title = "Double Y Axis", yaxis2 = ay,
      xaxis = list(title="x")
      )
  </code></pre>
  
  <p>I would really appreciate it if someone could offer some advice.</p>