[vue2] Update `@floating-ui/dom` dependency

[susnux]

Update the quite outdated dependency on @floating-ui/dom from v0.x to v1.1

I am using your package for a vue2 project but the dependency on v0 of floating-ui causes a dependency clash, so I would appreciate updating the dependency for 1.0.0-beta.20.

[antfu]

We are thinking of porting the vue2 version into the main branch as a separate package, which will make it much easier to maintain.