fix(typescript): include @types/node instead of shimming process

Author: yyx990803

packages/@vue/cli-plugin-typescript/generator/template/src/shims.d.ts

@@ -1,7 +1,3 @@
-declare var process: {
-  env: { [key: string]: string }
-};
-
 declare module '*.vue' {
   import Vue from 'vue';
   export default Vue;

packages/@vue/cli-plugin-typescript/package.json

@@ -26,7 +26,8 @@
     "globby": "^7.1.1",
     "ts-loader": "^3.3.1",
     "tslint": "^5.9.1",
-    "typescript": "^2.6.2"
+    "typescript": "^2.6.2",
+    "@types/node": "^9.3.0"
   },
   "devDependencies": {
     "@babel/plugin-proposal-class-properties": "7 || ^7.0.0-beta || ^7.0.0-rc",