I can't get Waterfall graph to render, it seems to just render a
regular line chart. The same graph works on 5.4.1+dfsg-1.

https://plotly.com/python/waterfall-charts/

sample modified to output HTML

```
import plotly.graph_objects as go

fig = go.Figure(go.Waterfall(
    name = "20", orientation = "v",
    measure = ["relative", "relative", "total", "relative", "relative", "total"],
    x = ["Sales", "Consulting", "Net revenue", "Purchases", "Other expenses", "Profit before tax"],
    textposition = "outside",
    text = ["+60", "+80", "", "-40", "-20", "Total"],
    y = [60, 80, 0, -40, -20, 0],
    connector = {"line":{"color":"rgb(63, 63, 63)"}},
))

fig.update_layout(
        title = "Profit and loss statement 2018",
        showlegend = True
)

fig.write_html("example.html")
```

Hey,
Thanks for reporging this. I've tried to reproduce the
issue using plotly 5.20.0+dfsg-1. (I uploaded to unstable this version today)
However, I was able to create a waterfall chart with the snipped you have shared.
(See the attached screenshot)

Could you verify if you're able to render the waterfall chart in this version?

Thanks!

---
Josue Ortega
«Happy Hacking»