Cannot use with Postcss 8 plugins

[philwolstenholme]

#41 means that rollup-plugin-vue is not going to be updated, which causes an issue for Postcss users as rollup-plugin-vue uses rollup-plugin-postcss version 3 and rollup-plugin-postcss only supports postcss version 7.

This means that if an 11ty user wants to use an up-to-date Postcss plugin (one that requires Postcss 8) with the rollupPluginVueOptions.style.postcssPlugins option then they will get this sort of error:

[11ty] Error: PostCSS plugin autoprefixer requires PostCSS 8.
[11ty] Migration guide for end-users:
[11ty] https://github.com/postcss/postcss/wiki/PostCSS-8-for-end-users (via Error)
[11ty] 
[11ty] Original error stack trace: Error: Error: PostCSS plugin autoprefixer requires PostCSS 8.
[11ty] Migration guide for end-users:
[11ty] https://github.com/postcss/postcss/wiki/PostCSS-8-for-end-users
[11ty]     at Object.<anonymous> (/Users/phil/Sites/wolstenhol-11ty/node_modules/rollup-plugin-vue/dist/rollup-plugin-vue.js:273:35)
[11ty]     at Generator.next (<anonymous>)
[11ty]     at fulfilled (/Users/phil/Sites/wolstenhol-11ty/node_modules/rollup-plugin-vue/dist/rollup-plugin-vue.js:30:58)

[zachleat]

The Eleventy Vue Plugin 1.x canary supports this and will go stable soon. The downside here is that it requires Vue 3!