Coloraxis not properly updated #167

In this codepen example, I have a simple scatterplot with a single data point, and a "coloraxis" marker.

When the datapoint's marker is updated, the coloraxis is not properly updated. Specifically, when the datapoint marker color is incremented or decremented, the coloraxis does not rescale as you'd expect.

For example, when the chart is initialized, the datapoint's color is initialized to 5. The color axis values range from 4-6, as you'd expect:

The Data.color++ and Data.color-- buttons increment and decrement the datapoint's color value. But this results in the coloraxis expanding to encompass the datapoint's color value from previous renders. Here, I've incremented and decremented the color a bunch of times, and the color axis' values now range from 0-12:

If I force the component to unload and reload (by passing a new React key param to the <Plot/> each time render is called), the issue is fixed. (Also, if I download the plot as a PNG, that PNG looks correct.)