Update dependency autoprefixer to v10

Author: renovate[bot]

package.json

@@ -26,7 +26,7 @@
   },
   "license": "MIT",
   "devDependencies": {
-    "autoprefixer": "9.3.1",
+    "autoprefixer": "10.4.20",
     "babel-core": "6.26.3",
     "babel-loader": "7.1.5",
     "babel-plugin-transform-runtime": "6.23.0",