fix: reuse ident of css related loaders to avoid duplicates (#1233)

lib/plugin.js

@@ -145,11 +145,19 @@ function cloneRule (rule, normalizedRule) {
   return res
 }
 
-const reuseIdentWhitelist = /css-loader/
+const reuseIdentWhitelist = [
+  'css-loader',
+  '(vue-)?style-loader',
+  'postcss-loader',
+  'extract-text-webpack-plugin',
+  'mini-css-extract-plugin'
+]
+
+const reuseIdentPattern = new RegExp(`(${reuseIdentWhitelist.join('|')})`)
 
 function cleanIdent (use) {
   if (use.ident) {
-    if (reuseIdentWhitelist.test(use.loader)) {
+    if (reuseIdentPattern.test(use.loader)) {
       // Reuse options ident, so that imports from within css-loader would get the
       // exact same request prefixes, avoiding duplicated modules (#1199)
       use.options.ident = use.ident