bump to 2.0.0-alpha.2
bump to 2.0.0-alpha.2

uwdata/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,vega/vega-lite,vega/vega-lite,vega/vega-lite