fix: remove postcss.config from schema (#9181)

packages/schema/src/config/postcss.ts

@@ -4,10 +4,6 @@ import { defineUntypedSchema } from 'untyped'
 
 export default defineUntypedSchema({
   postcss: {
-    /** Path to postcss config file. */
-    /** @type string | false */
-    config: false,
-
     /**
      * Options for configuring PostCSS plugins.
      *

packages/webpack/src/utils/postcss.ts

@@ -60,16 +60,6 @@ export const getPostcssConfig = (nuxt: Nuxt) => {
     return false
   }
 
-  const configFile = nuxt.options.postcss.config
-  if (configFile) {
-    return {
-      postcssOptions: {
-        config: configFile
-      },
-      sourceMap: nuxt.options.webpack.cssSourceMap
-    }
-  }
-
   let postcssOptions = cloneDeep(nuxt.options.postcss)
   // Apply default plugins
   if (isPureObject(postcssOptions)) {