please support vite 'css.devSourcemap' config

[cnzgray]

Looking at the source code of style in @vite/plugin-vue, you can find that there is a piece of code as follows(https://github.com/vitejs/vite/blob/HEAD/packages/plugin-vue/src/style.ts#L26):

  const block = descriptor.styles[index]
  // vite already handles pre-processors and CSS module so this is only
  // applying SFC-specific transforms like scoped mode and CSS vars rewrite (v-bind(var))
  const result = await options.compiler.compileStyleAsync({
    ...options.style,
    filename: descriptor.filename,
    id: `data-v-${descriptor.id}`,
    isProd: options.isProduction,
    source: code,
    scoped: block.scoped,
    ...(options.cssDevSourcemap
      ? {
          postcssOptions: {
            map: {
              from: filename,
              inline: false,
              annotation: false
            }
          }
        }
      : {})
  })

There is an option to turn off the sourcemap output of css. And that option comes from the configResolved hook in index.ts.(see https://github.com/vitejs/vite/blob/HEAD/packages/plugin-vue/src/index.ts#L132)

By tracking the compilation process of vite, it is not difficult to find that the preprocessing of vite's style does not output a sourcemap under the action of the css.devSourcemap configuration, but the current plugin directly provides a sourcemap, which leads to inconsistency in behavior.