fix: add timeout for requests

closes #3076

Author: haoqunjiang

packages/@vue/cli-shared-utils/lib/request.js

@@ -4,6 +4,7 @@ exports.request = {
     const request = require('request-promise-native')
     const reqOpts = {
       method: 'GET',
+      timeout: 30000,
       resolveWithFullResponse: true,
       json: true,
       uri