enable global consistency of color mapping between animation frames

Hi, Thanks for this AWESOME project. I really enjoy using it.
The animation function can't keep the global consistency of color mapping between animation frames.

Here is an example in Colab for my use case. In this example, I use Plotly.py with scatter_geo API. My code is as between,

import plotly.express as px
df = px.data.gapminder()
fig = px.scatter_geo(df, locations="iso_alpha", 
                     color="lifeExp",
                     hover_name="country", 
                     size="pop",
                     animation_frame="year",
                     projection="natural earth")
fig.show()

I expect the color mapping for lifeExp to keep consistent between different frames, which means the same color among frames should represent the same lifeExp value and the color bar should keep the same too. But the result looks like below, in which the frames in 1952 and 1997 can't be comparable.

I would expect some API like,

fig = px.scatter_geo(df, locations="iso_alpha", 
                     color="lifeExp",
                     keep_color_global_consistency = True,
                     hover_name="country", 
                     size="pop",
                     animation_frame="year",
                     projection="natural earth")

eg, it has keep_color_global_consistency option and the default value should be True.

首先，使用 scatter_geo、color 和 animation_frame 复现链接的 Colab 示例。了解动画帧之间如何处理颜色映射和颜色条，然后定义 API 行为，使相等的值使用可比较的颜色，并使颜色条保持固定；当 1952 年和 1997 年的帧可以直接比较时，即视为完成。