execlastid doesn't respect support_big_numbers

[yshrsmz]

related: #13, #15

sqlc-gen-typescript/examples/node-mysql2/src/db/query_sql.ts

Lines 94 to 100 in 1a42ab0

	export async function createAuthorReturnId(client: Client, args: CreateAuthorReturnIdArgs): Promise<number> {
	const [result] = await client.query<ResultSetHeader>({
	sql: createAuthorReturnIdQuery,
	values: [args.name, args.bio]
	});
	return result?.insertId ?? 0;
	}

This method should return string as support_big_numbers and big_number_strings is enabled in sqlc.dev.yml

sqlc-gen-typescript/examples/sqlc.dev.yaml

Lines 43 to 54 in 1a42ab0

	- schema: "authors/mysql/schema.sql"
	queries: "authors/mysql/query.sql"
	engine: "mysql"
	codegen:
	- plugin: ts
	out: node-mysql2/src/db
	options:
	runtime: node
	driver: mysql2
	mysql2:
	big_number_strings: true
	support_big_numbers: true

This is because I explicitly declared a return type as number here

https://github.com/sqlc-dev/sqlc-gen-typescript/pull/13/files#diff-2078b150759ca61c4ae2bb37cb070f5a2d81e64c7b4d1aa126f621e2520f13d0R641-R643

but should respect PK's type.

[yshrsmz]

@kyleconroy How can I find out PK's type?
I checked every value in GenerateRequest, but could not find one.

AFAIK, we can return Promise<string | number> from :execlastid, but it's not possible to define explicit type with current information.