remove dependency

package.json

@@ -37,7 +37,6 @@
     "rollup": "^2.2.0",
     "rollup-plugin-babel": "^4.4.0",
     "rollup-plugin-peer-deps-external": "^2.2.2",
-    "rollup-plugin-postcss": "^2.5.0",
     "rollup-plugin-terser": "^5.3.0",
     "@rollup/plugin-commonjs": "^11.0.2"
   },