chore(package): update autoprefixer

Author: Awk34

Diff for: templates/app/_package.json

@@ -104,7 +104,7 @@
 
     <%# END CLIENT %>
 
-    "autoprefixer": "^7.1.3",
+    "autoprefixer": "^8.6.0",
     "babel-eslint": "^8.2.3",
     "babel-register": "^6.16.0",
     "bs-fullscreen-message": "^1.0.0",