Add `useBigInt` option to TypeScript definitions

The current copy of https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/sql.js/index.d.ts does not have any reference to useBigInt, so I am unable to pass that option in to exec() statements. Whoever is the maintainer of those TypeScript defs, could you please add this new option?

Start with types/sql.js/index.d.ts in DefinitelyTyped, which the issue identifies as missing the useBigInt option for exec() statements. Check the existing exec() definition and the sql.js API reference for that option, then update the declaration so TypeScript accepts it and verify the definition compiles.