feature: 解决跨域问题

config/plugin.local.ts

 export default {
-  cors: {
-    package: 'egg-cors'
-  },
   webpack: {
     package: 'egg-webpack'
   },

config/plugin.ts

 export default {
+  cors: {
+    package: 'egg-cors'
+  },
   vuessr: {
     package: 'egg-view-vue-ssr'
   },

typings/config/plugin.d.ts

@@ -14,9 +14,9 @@ import 'egg-schedule';
 import 'egg-static';
 import 'egg-jsonp';
 import 'egg-view';
+import 'egg-cors';
 import 'egg-view-vue-ssr';
 import 'egg-sequelize-ts';
-import 'egg-cors';
 import 'egg-webpack';
 import 'egg-webpack-vue';
 import { EggPluginItem } from 'egg';
@@ -34,9 +34,9 @@ declare module 'egg' {
     static?: EggPluginItem;
     jsonp?: EggPluginItem;
     view?: EggPluginItem;
+    cors?: EggPluginItem;
     vuessr?: EggPluginItem;
     sequelize?: EggPluginItem;
-    cors?: EggPluginItem;
     webpack?: EggPluginItem;
     webpackvue?: EggPluginItem;
   }