Export Size type for typescript

[Maximaximum]

This is not a huge issue, but it would be just a little bit more convenient if the library also exported a Size type within its typings:

export declare interface Size { width: number; height: number; }
export declare type ResizeSensorCallback = (size: Size) => void;

instead of just

export declare type ResizeSensorCallback = (size: { width: number; height: number; }) => void;

The issue is that the type of the ResizeSensorCallback argument sometimes has to be specified explicitly, so this minor change would help to avoid retyping { width: number; height: number; } in such cases

[marcj]

@Maximaximum feel free to create a PR covering this change. 👍

[marcj]

Ops, you already did :D thanks!

[Maximaximum]

@marcj thank you. Could you please give a hint regarding when you plan to reslease a new version containing this change?