fix: explicitly set corejs version for @babel/preset-env (#3696)

closes #3695

Author: haoqunjiang

package.json

@@ -76,10 +76,7 @@
     "yorkie": "^2.0.0"
   },
   "resolutions": {
-    "@babel/core": "^7.0.0",
-    "@babel/preset-env": "^7.0.0",
     "babel-core": "7.0.0-bridge.0",
-    "ps-tree": "^1.1.1",
     "puppeteer": "1.11.0",
     "vue": "^2.6.7",
     "vue-template-compiler": "^2.6.7",

packages/@vue/babel-preset-app/index.js

@@ -123,7 +123,8 @@ module.exports = (context, options = {}) => {
     include,
     exclude: polyfills.concat(exclude || []),
     shippedProposals,
-    forceAllTransforms
+    forceAllTransforms,
+    corejs: 2
   }
 
   // cli-plugin-jest sets this to true because Jest runs without bundling

packages/@vue/babel-preset-app/package.json

@@ -26,8 +26,8 @@
     "@babel/plugin-proposal-decorators": "^7.1.0",
     "@babel/plugin-syntax-dynamic-import": "^7.0.0",
     "@babel/plugin-syntax-jsx": "^7.0.0",
-    "@babel/plugin-transform-runtime": "^7.0.0",
-    "@babel/preset-env": "^7.0.0",
+    "@babel/plugin-transform-runtime": "^7.4.0",
+    "@babel/preset-env": "^7.4.1",
     "@babel/runtime": "^7.0.0",
     "@babel/runtime-corejs2": "^7.2.0",
     "@vue/babel-preset-jsx": "^1.0.0-beta.2",