color attribute not supported

[farresti]

In the current version of plost 0.2.5, color attribute of every chart type is not supported.

Looking in the code, there seem to be a lack of passing through the value of the color argument.

One easy fix is to replace every

spec = D(
        mark=D(type='circle', tooltip=True),
        encoding=D(
            x=_clean_encoding(data, x),
            y=y_enc,
            color=color_enc,
            size=_clean_encoding(data, size, legend=legend),
            opacity=_clean_encoding(data, opacity, legend=legend),
        ),
        selection=_get_selection(pan_zoom),
    )

by

spec = D(
        mark=D(type='circle', tooltip=True),
        encoding=D(
            x=_clean_encoding(data, x),
            y=y_enc,
            color=_clean_encoding(data, color),
            size=_clean_encoding(data, size, legend=legend),
            opacity=_clean_encoding(data, opacity, legend=legend),
        ),
        selection=_get_selection(pan_zoom),
    )

The change is in the line color=color_enc to color=_clean_encoding(data, color).