Pass correct arguments for create routines to constructors

[shadowspawn]

Problem: Not passing through correct number of options for createOption.

I got the methods and arguments tangled in the previous PR: #23

See: #22 and #22 (comment)

A more careful comparison...

Underlying Javascript

createCommand(name)
createOption(flags, description) 
createArgument(name, description)

TypeScript declaration

export function createCommand(name?: string): Command;
export function createOption(flags: string, description?: string): Option;
export function createArgument(name: string, description?: string): Argument;

New implementation

exports.createCommand = (name) => new commander.Command(name);
exports.createOption = (flags, description) => new commander.Option(flags, description);
exports.createArgument = (name, description) => new commander.Argument(name, description);

[shadowspawn]

Note: this PR includes a fix for the tests on Node 14. Added some runtime tests, which means now need Commander installed too for the tests which does not happen by default on Node 14.

Used Jest for the tests which is overkill for just 3 tests currently, but is what we use in Commander so familiar and will allow moving tests between repos when useful.

[abetomo]

This is awesome!