Dioxus branch needs update

[WestXu]

So dioxus 0.1.8 made an api breaking change from this:

let mut count = use_state(&cx, || 0); // 0.1.7

to this: (discussions see DioxusLabs/dioxus#129)

let (count, set_count) = use_state(&cx, || 0);  // 0.1.8

And this new api is what the dioxus branch of this repo uses.

Now dioxus 2.0 came out, with this api change reverted somehow. What we need is to adapt to this revert, and bump the dep version up to 2.0.

@羽田

[WestXu]

#8
Finished.