fix required fields in the schema
fix required fields in the schema

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