fix(csv-demo-esm): ts type

Author: wdavidw

demo/esm/lib/parse_sync.ts

@@ -2,7 +2,7 @@ import assert from "assert";
 import { parse } from "csv-parse/sync";
 
 // Create the parser
-const records: [] = parse(["a:b:c\n", "1:2:3\n"].join(""), {
+const records: string[][] = parse(["a:b:c\n", "1:2:3\n"].join(""), {
   delimiter: ":",
 });
 // Test that the parsed records matched what's expected