feat: enable mouse move event when mouse is pressed on macos

[HuakunShen]

On MacOS, when mouse is pressed, no move event is emitted.
This prevents me from detecting drag event.

On both windows and linux, move event is emitted when mouse is pressed.

I think it's a better idea to add MouseDrag event to EventType, because Mac's native API already have this CGEventType::LeftMouseDragged.

But this requires also updating windows and linux API to stay consistent.
I may work on that later. This PR makes rdev behave the same way on all platforms.

[rustdesk]

@fufesou

[fufesou]

This PR works good.

1. Could you please change the example filename. simple.rs is not a good name.
2. Is there any way to support center(scroll) button, forward and backword buttons? This API is not good enough to support those events

   rdev/src/macos/listen.rs

   Line 46 in f9b60b1

   let tap = CGEventTapCreate(

I think it's a better idea to add MouseDrag event to EventType, because Mac's native API already have this CGEventType::LeftMouseDragged.

I'm not sure about it. Press flag and MouseMove event look enough to me.

[HuakunShen]

@fufesou I removed the simple.rs example