update deps

package.json

@@ -44,7 +44,7 @@
     "@semantic-release/github": "^7.0.4",
     "@vue/compiler-sfc": "^3.2.20",
     "@vue/test-utils": "^2.0.0-rc.16",
-    "autoprefixer": "^9.4.7",
+    "autoprefixer": "^10.3.7",
     "babel-core": "^7.0.0-bridge.0",
     "babel-eslint": "^10.0.3",
     "babel-loader": "^8.0.5",
@@ -54,7 +54,7 @@
     "coveralls": "^3.0.2",
     "cross-env": "^5.2.0",
     "css-loader": "^2.1.0",
-    "cssnano": "^4.1.10",
+    "cssnano": "^5.0.8",
     "cz-conventional-changelog": "3.1.0",
     "eslint": "^6.8.0",
     "eslint-config-prettier": "^6.10.0",

postcss.config.js

@@ -1,5 +1,6 @@
 module.exports = {
   plugins: [
+    require('postcss-import'),
     require('postcss-nested'),
     require('autoprefixer'),
     require('cssnano')({