add dayOfYear methods for moment.js

Signed-off-by: Malesh <andrew.sampson@gmail.com>
is this right? I think `dayOfYear(d: number): Moment;` is collect.
https://github.com/moment/moment/blob/2f9b330eb35a38184fd7239749c7f0feef6c5146/moment.js#L2484
https://github.com/malesh/DefinitelyTyped/blob/2b1a6d772c3c79048068a3b94f280de478d69fed/moment/moment.d.ts#L96