feat: add pixi v8

[random-yang]

[gnykka]

@random-yang hey, sorry for the slow response here.
Do you think it's useful to have both Pixi pages at once? Or maybe migrate the current Pixi example to work with v8?

[random-yang]

@gnykka I think it makes sense to let people clearly compare two major versions of pixi. After all, there are significant changes in v8 compared to the previous version, and it's important to make people aware of these changes.