chore(package): update autoprefixer to version 8.6.3 (#82)

Author: gucong3000

package.json

@@ -7,7 +7,7 @@
     "postcss": ">=5.0.0"
   },
   "dependencies": {
-    "autoprefixer": "^8.3.0",
+    "autoprefixer": "^8.6.3",
     "known-css-properties": "^0.6.1",
     "normalize-range": "^0.1.2",
     "postcss-selector-parser": "^4.0.0",