generateCsv() doesn't work with plain object rows.

[mikelehen]

I created a row interface:

interface ResultRow {
  year: number;
  regionId: string;
  variable: string;
  value: number;
}

And then tried to use it with generateCsv():

const rows: ResultRow[] = [];
generateCsv(rows);

But I get:

Argument of type 'ResultRow[]' is not assignable to parameter of type 'DataRow[]'.
Type 'ResultRow' is not assignable to type 'DataRow'.
Index signature for type 'string' is missing in type 'ResultRow'.ts(2345)

I think we should try to tweak the types to try to make this work...