[feature request] BigInt support

[dhbaird]

// Expect this:
console.log(sprintf("%d", 9999999999999999999999999999999999999999n));
// To print this:
// 9999999999999999999999999999999999999999

// But instead, an error such as the following is generated:
sprintf-js/src/sprintf.js:61
                if (re.numeric_arg.test(ph.type) && (typeof arg !== 'number' && isNaN(arg))) {
                                                                                ^

TypeError: Cannot convert a BigInt value to a number

Thanks!