Feature request

What problem does this feature solve?

As far as I can tell, Vue 2 and 3 are not compatible, i.e. you cannot bundle a Vue 2 component using Rollup and then consume it from a Vue 3 component. This means component libraries that document their components using Vuepress won't be able to upgrade to Vue 3 until Vuepress supports it.

Are you willing to work on this yourself?

I'm not super familiar with Vuepress, but I'm happy to help. The reason I'm asking is because I would like to upgrade a Vue project I work on to Vue 3 as soon as it's released, but that entails upgrading its dependencies first. One of those dependencies is a component library that uses Vuepress for its documentation, so they can't upgrade until Vuepress does.

Is there an existing branch where work on Vue 3 compatibility has been started? If not, can one be created so we can open pull requests to it?