chore: 更新postcss.config.js文件为esm语法

.eslintignore

@@ -6,7 +6,7 @@ package.json
 .eslintrc.cjs
 .prettierrc.js
 commitlint.config.js
-postcss.config.cjs
+postcss.config.js
 tailwind.config.ts
 stylelint.config.cjs
 src/components/ReSplitPane/iconfont

postcss.config.js

@@ -1,4 +1,7 @@
-module.exports = {
+// @ts-check
+
+/** @type {import('postcss-load-config').Config} */
+export default {
   plugins: {
     "postcss-import": {},
     "tailwindcss/nesting": {},